BUMPING this because they were out. I emailed them asking some questions, and then they changed it to back in stock. So they do have these again.

 

3.7 inline 5, and yeah - very Colorado/Canyon-esque but trimmed nicer & a little more robust in a number of ways.
inside looks just like the google pictures... except ours has a Core/Hurst shifter in it now (which shifts like a DREAM).

the impression i got from working with him is that since he typically builds these to order nowadays, he'll buy a bunch of common parts when people ask for a specific shifter - then make a few & then sell them, then once he's out of parts, he'll wait 'til he needs to build more before ordering again... or i think that's how it goes.

either way, compared to the original Hurst i had in my nv3500, his nv4500 unit was on par with or better than it - still a little finicky at times, and the stick angle put the ball against the console in 4th, but overall i still liked it more than the stock box (also ensure you get the correct height & pivot length for your transmission lid). and the H3 shifter he made us (of which, i only know of one or two others that were built) is amazing!

and all this thread resurrection business reminds me of right before i bought the dodge... i almost pulled the trigger on a 2000 Tahoe to do this very nv4500 swap in.
come to think of it, had i bought the Tahoe, i'd have a lot more cash in my pocket right now... but i also wouldn't have almost 1400lb of torque or 6 gears.

 

oh, and as alluded to above: only use GL-4 fluid in the nv4500 (AmsOil has some reasonable stuff that works good), and i learned from the shop that rebuilt my 4500 to NOT overfill it. that works for 3500s & 5600s but apparently overpressurizes the seals or something in a 4500 & will cause it to leak.

(ps - i also learned during my nv4500 swap that the nv3500 uses the same flywheel & slave cylinder... if you need to pinch a couple pennies).

 

I am thinking about doing this manual trans swap in a Yukon xl with the 8.1. Really want to turn it into a off-road camping rig monster. Roof rack, bumpers, lift tires the who deal. I had been thinking a Duramax swap with the Alison, would be the way to go not great for off-road to have that weight. Still I would just enjoy the 8.1 while I do all the other stuff. BUT now I am think a manual swap would cost less, witch is good for something I will more than likely put dents in. And work better for my intended use.

 

sounds fun enough!
one thing to keep in mind for your big block is that while the pickups had the Allison or ZF-S6-650 as options, the SUVs only used 4L85s.
the biggest difference that makes is that the SUVs never needed (or got) the normal 2" HD body lift to fit the bigger transmissions. that said: your options would be to either do an nv4500 with the shorter GMT400 lid or add a body lift & use the 6 speed.