If you're really serious about tackling these sorts of projects, bite the bullet, sink the cash into a decent welder, and start practicing. The welder cost will likely be in the noise floor of the total costs of the vehicle. It takes a long time to get decent at TIG, and you're unlikely to do it by occasionally borrowing someone elses equipment every other weekend or so.
As for the English Wheel; if you get a welder that can do both stick and AC/DC TIG, build your own English Wheel as one of your earlier welding projects.
The english wheel is a *really* beefy framed piece of equipment. Even if you had a large enough TIG torch to handle welding it up, why would you want to? It would take forever, and not really make you any better at TIGing the thinner aluminum stuff. Big beefy stuff you use MIG or stick. Many TIG units will also do stick, not so many will also do MIG. The ones that can are mondo pricey last time i was looking.