For $5k, go buy the TW!!!!!!!!!!!!!!!!!!!!!!! I tried building one, I am still building it!!! (look it up, there's even a video of it, before it broke, again)
27hp Kawi. twin, watercooled 3hrs on it $500, 28GPM Haldex $350, hoses $750 (I got them down to $450 as they quoted me on the phone) 3/4 ton rear axle, free, steel, free, I-beam -$50, 6"x24" cylinder, free, control valve, free, $100 in wiring, switches and an hour meter. $100 for a jack and hitch. $150 in hyd. fluid. Three burnt up angle grinders, one burnt up shop saw, filled my oxy/accet. rig four times. 30#'s of rod, I have no idea how many grinding wheels and cut off wheels. A few all nighters, plus I don't know how many hours of scrounging for material cutting 1 1/4" steel, more slag burns than I could count. And oh yeah, it's run about two hours!
I get the "I built it" coolness, but it really isn't worth it if you really want to get down to the nitty gritty, how much money would I have made splitting wood vs. all time I spent building this thing?
I really hate to be a spoil sport, but unless you are a MacGyver type (Patrick!!!!) you aren't whipping one up in a weekend!!!