There are a few vendors out there but no one is cheap. You can even get a fox body style seat with the 65 66 style seat covers on them if you wanted. Some have swap seat tracks them selves on the newer style seats and installed them in there cars.
I got my Supra seats for free, and had them re-upholstered at a community college for the cost of materials. Under $150 for front seats, rear seats, and center console.
I installed Corbeau A4s in my '67. I got them on a group buy for 16 percent off--about $550 total. I modified my existing brackets to fit. I'm 6-foot-5, and the A4s actually give me a little more headroom than the stock buckets did, with no seat riser modifications. They are snug, however; if your waist is more than 36 inches (34 is better) then don't bother.