Your best choice would be the rare Meister Brau pull tractor as mention in previous email, the kit was introduced in the mid-80's by Amt/Ertl, this one was a real show beast like you see in pull tractor shows, 3 engines inline, extended frame, extra beefy mud traction tires & a lot of shiny chrome, really nice kit, with all those high performance parts fitted for pull & show tractors, but not a big sale succes was discontinuated in the early 90's. was not remarketed since then.
If you need a starting base try the 70's 80's ERTL kits, like mention earlier, the JD in farm version & also construction back-hoe version was repop back in the late 90's after a long retirement.
Check eBay, some still show up from time to time...but the Meister Brau kit is not cheap!