i beams are a lot less expensive to get lots of travel out of than a-arms. if it were me and i was building it strictly as a toy, i would get a 97 or older ranger with a 4.0 and 5 speed.
i'd talk to dave at threat motorsports (i believe hes a site sponsor on here) about getting some of his beams for the front end, and i think he has a special going right now for either 3 or 4 link kits for the rear end. buying used shocks can save you some money if you know how to rebuild/revalve them (easier than it seems), but they wont look knew; otherwise new will get you the same thing as rebuilt shocks, just shiny. as far as cage work goes, you'll at least need an engine and bed cage, but for a long travel and linked truck you'll for sure want a cab cage. i dont know how much tubing, but an estimate for cab cages is 200-220 feet of tube to do it right. prices change on that all the time, so i cant give numbers. good seats will set you back a few hundred each, and then if it were me i would buy new harnesses instead of used. a race radio is a necessity these days, and a new one will set you back around 350 for radio and antenna. fiberglass is around 350 for both front fenders and 450 for bedsides i thinnk, dont quote me on that.
in the end, whatever you thought it would cost, double that amount and you then might have enough money.