I agree with showing them you can weld. It don't matter what you show up with, I think one of the guys said he started in a vw bug with a single axle trailer as his rig on another thread. On the other hand, first impressions, as we've all done or are guilty off can be a factor, sad but true. I've run across this in my years as a mechanic. You get into a new shop and everyone looks at ya funny. You pull a head off a series 60 detroit and swap head gasket and get it back together and out the door by the end of the day and everyone in the shop looses that funny look and starts to talk to you. Only questions asked were where is this tool at specific for the engine. People are gonna need to see what you can do, heck I've thought about my resume and instead of doing the traditional one just email them pictures of the things I've built, stairs, handrails and so on may serve better than words because I can explain to people all day long what I've done and you can see it in their eyes that they are skeptical. My first night back at school a few months ago I told the teacher that I could run 7018 up/down/sideways etc. I could see he was skeptical. That first night while I was welding my first 3g he would poke his head in and not say much. The third night I nailed my 3g. Later I learned while talking to the teacher, he said, "I knew you knew what you were doing the first night you were here", He continued to say he could tell just by the sound of the rod burning while I was welding that the machine was set right, he could see as the slag peeled off by itself and how the welds looked.
My rig is just a plain ol' western hauler flatbed with a aluminum truck box on one side and a God awful looking homemade box on the other. Made it from an old fuel tank off a generator that I got for free, works for now til I can afford the steel to make one how I like it...still can't stand the sight of it though!! Then I've got my Lincoln Ranger 8 air cooled, all I can afford at the moment until I can scrounge up something better when the cash is available. Would I get laughed at, maybe, perhaps while I drive down the road other rigs look and giggle, don't know don't care. There is a guy around here that is running a utility bed on his truck, F450/550. He does a bunch of construction equipment repair, has a crane etc. I guess that welding rigs could be specific for an environment or type of work you do? Pipeliners are gonna need certain things to do their jobs, guys doing heavy equipment repair may need more handtools thus requiring more space. I've got a ton of wrenches, sockets and so on behind the seat in the truck I would like to move onto the bed if I had space so I could have space for all the extra winter clothing.
I think someone said, look at other beds, think of what you like, don't like and what it is your going to do and design your own bed specific for your needs. Then you can start on it little by little. Or you can buy a flatbed, utility bed or one like Uphill did with the orange truck above and modify it to how you want it.
Learn every process you can, it's just better for you. I can do stick/mig and learning tig now. The more you know the better off you are, if tig is for p###ies.....guess I am, but I can roll up under a machine and lay there getting the t total crap burned out of myself with the best of them. Spent 3 months on Parris Island getting eat up by bugs and not being able to swat them, think I can handle some burns!