Well I finally broke down and did it. Thought I'd break it down for those interested.

First, build your cable reels. I used old hub bearings picked up at the local dealer. No core on these things and you may be able to talk a mechanic into holding a couple for you.
I used 2" or 2 1/4" exhaust pipe for the center section on one, old scrap for the negative side. I cut off the center of the hub bearing where it sticks up to center the tire with a plasma cutter then situated my exhaust pipe on the center of that, leveled it and welded. I cut out 4 10" round plates and two had holes in the center the same size as the hole for the splined driveshaft. After getting the reels built I mounted them onto a piece of 10" channel at a predetermined angle to give it a bit of slope back towards the cab of the truck, why? I don't know.

Now, my ground reel I decided would be on top. I simply found a washer that would fit down inside the hole of the hub bearing, put a 1/2" bolt coming out of the washer and welded the bolt to the washer(thick washer, maybe 1/2" itself) Then I put that down into the hub bearing and welded it into place. Next was putting a 1/2" lug on the reel itself. Simply cut a 1/2" bolt and welded it into position. Now your ground reel is done.

Positive reel. I've posted pics so you can follow, pics are in order, any questions feel free to contact me. Onto the assembly. Pick you up somo 3/4" pvc electrical grade conduit, a tube of plastic epoxy, 1/2" all thread and a 2 1/4" pvc union. First I determined where I wanted the lug to sit on the reel. Then I drilled a hole into one side and out the other. After this, depending on what size bit you have( I had a 5/8" so had to use a round file to enlarge the hole) You want the hole to be just large enough to fit the pvc through, the more round and perfect the better. To cut off your pvc I had mine stick up about 1/4" above the metal tube on either side. But before you put it in there you need to drill a hole through the side of it. Take your 1/2" all thread and get an estimate on how long it needs to be to hit the center of your drilled holes. Take a 1/2" nut and grind all the sides off making a nice little threaded round nut(see pics) This little piece will be welded to the end of your threaded rod as seen in pics. Now, insert the short pvc into the drilled holes. Take another piece of pvc and go through the hub bearing and get an estimated length and cut. Remove the short pvc and file the end of the long pvc so in contours perfectly around the short piece. What you'll have is a little "T". On the center of the short piece you need to drill a hole that will let the little round threaded circle fit through. Put your short piece back into the pipe, take the longer piece and apply pipe cement to the end where it will contact the short piece then install into the hub bearing and push firmly til it sticks. Now you can tip the reels on the side and mix up a bunch of the epoxy then pour it into the hub bearing around the extended piece of pvc. I got the 1 minute stuff and it set up and I could go on working away. This will stabalize the pvc.

Once it is cured cut off a short piece of all thread, the length is determined by the short section going through the center of the pipe. One side will have a nut and a washer, the other side will have a nut, washer and your cable lug. Next, take your pvc union and cut it in half length wise. Drill out a hole in each piece and file if need be so it fits over your gray electrical pvc, snuggly. This will isolate the cable lug a bit more from the metal pipe. Once I had my two halves filed out right I again put on some pipe cement and put them down over the top of the short gray pvc on both sides. I also cemented the two halves where I cut them, but only one side touched. Now you can take your long all thread with the welded circle on the end, put it throught the hub and pvc sleeve until it comes out into the short section. Then take your short piece of all thread and thread it through the eye to the other side. Install the nut and washer on both sides. The next thing I did was take a piece of 1/2" pvc about 7" long, drilled out the center with a 1/2" drill bit so it would slip over the 1/2" all thread. Then, if I had more epoxy I would have filled in the void with that to keep my all thread from wobbling, but I did'nt have anymore epoxy. So I cut off about 1" of 1/2" pvc the sectioned it length wise and wedged the little pieces between the gray and white pvc with some cement. The next thing is to measure up from your epoxy on the hub bearing about 1/2" and cut off the excess. Then the tricky part, sneak upstairs and grab your wifes Teflon cutting board(1/2" thick) bring it down to the shop and cut it dead in half. Return unused portion to kitchen sink. I used a 2 1/2" hole saw you cut out a washer, then drilled the center hole large enough to fit snug around the gray pvc.

The final chapter. Once I got everything isolated I wanted to isolate it from the truck. Soooooo, I took a piece of 3" angle, cut it off to about the same length as my angle channel. I cut out two pieces of the teflon cutting board, drilled three holes at random 1/2" diameter. This is so I can put in 3 1" pieces of 1/2" pvc to isolate the bolts that will be through and resting against the angle on both sides. Finally put the assembly in the bed of the truck, welded it to the bed and check with an ohm meter. The positive and negative reels are completly isolated from one another. Also the assembly is isolated from the bed of the truck. Not satisfied with the Ohm meter test I fired up the welder and hooked the ground to the ground reel lug, cranked the machine up to 225/max and put in a rod and began pecking at the positive lug and the truck bed. Contacting the frame of the cable reels and it would spark(obviously) but contacting the 3" angle just below it and nothing. You can connect both cables and then touch both reels and not get lit up like the fourth of July, no accidental there goes my truck computer moments and my total price on this was maybe $20. Built mostly with stuff I had laying around.

Now for pics,