I built one a few years ago for my '90 turbo LG5 3.1/ LA1 3400 hybrid. The mount I built is no way that complicated, and it works perfectly. I am using a 3400 block from a '99 GA/GT, and I retained the A/C compressor and bracket from the 3.1 MPFI engine. IIRC, I had to grind-down a little of that aluminum bracket to clear the oil-pan on the 3400, and the newer blocks are also lacking a mounting-bolt hole in the front of the block by the crank pulley to support the compressor bracket, but the mount I built supports the bracket at the top like the 2.8/3.1 engines originally did, so it is fine. I built one for another board member, and I made a spare for myself. I can make more of them if people are interested.
They aren't super pretty, but you really can't see them anyway. I just don't like that other mount because if you are off by a few degrees here or a fraction of an inch there, the errors will keep multiplying, and there are so many pieces to it that there are a lot of places where errors can creep in. And IIRC it doesn't support the older-style A/C bracket at all.
Here are a couple of pics of my spare mount, the one I built for the other board member is quite a bit beefier due to his HP goals, and has a longer webbing across the top. I have complete confidence in this one though, considering that the steel it is made from is 2-3 times thicker than the frame-side mounting point in the car itself...
The newest version also has the option to be bolt-together so the top-half and the bottom-half can be adjusted in case someone wants to tweak the engine up, down, forward or backward a tiny bit. On my '90 turbo 'Retta for instance, I brought my engine up ~1/2 inch to help clear the bigger T-4 turbo parts I upgraded from the LG5's original turbo setup, without having to hack-up the car's transmission-mount bracket.
And if someone doesn't have any interest in using the older-style A/C compressor, then that tab on the bottom can just be deleted, which saves me some time building it.
If anyone wants one, just PM me, and we can discuss price -mine wouldn't cost as much as the other mount either since it just isn't as complicated to build. It would take me a few days to put one together and ship it out.