I was thinking the same thing, I am in the process of adapting the Glide to my 2jzgte and this is the cost so far...
975.00 for a Glide from Transking(they advertise in National Dragster weekly and build race tranny's for alot NHRA bracket racers) The glide is there "sportsman glide" which will handle up to 900hp and comes with a turbo spline input, hardened shaft, and Pro tree transbrake. As far as the converter, they said all I need to do is take some measurements(with regards to the flywheel v. converter fully installed in the tranny) and then send them the flywheel and they will mount the tabs to the converter to match the flywheel...all this for 650.00) I am going with a 4500 stall in my case, but you can make the call on what stall speed you want. Then, an adapter plate from Paisley automotive is only 650(and I will be making my own out of 1/8 mild steel, but for the sake of argument, lets say you buy the adapter plate) You then have a shifter 150-200 and of course SFI approved flywhell shield(100 from JEGS) and SFI approved trans shield(200 from jegs) Custom driveshaft varies, but I had one made for 200 last time I needed one to convert a toyota pickup rearend to a chevy turbo 350. Grand Total-2800(and if you make the plate yourself, only 2150...) Where do they come up with 5000-6000, heck, you can even get a pro glide, with SFI approved Dedenbear case and bellhousing, aftermarket gears, 4340 shaft for 2600.00) and this tranny will hold 1500hp...
A freind of mine runs the Transking Glide and he went the entire race season(he has 496 big block that runs 9.40's in a Chevelle) approximately ten races, plus numerous test and tunes and it lasted the entire season without failure, he just sent it in to have it "refreshened" it was only 200 bucks! Now, lets see anyone do that with a supra auto tranny! Of course the glide is for vehicles under 3000pounds and is drag only, but heck, thats what alot of us want anyway!
Transking also does turbo 350's/400's too...
Dave