I'm fairly certain the LS4 uses a different style alternator than most other LS engines, but I could be wrong. Either way, I have one here, and used it to validate the model shown in one of the above pictures.
I cut prototypes yesterday morning when I got off work, the parts fitup looked good initially, but I found a few issues.
This plate that bolts to the side of the block, I measured slightly wrong, I had the holes to close together by about 2mm, so the bolts would not go in. I used the back bolts for the rest of the test fitting.
The pulley offset was WAY wrong, this was not unexpected, I quickly took the measurements, dropped them into CAD, unfortunately I didn't adequately label everything, and later when I was working on it couldn't remember which mark was the right offset, I should have measured before cutting, but you know, if you're gonna be wrong, be confidently wrong. unfortunately, this offset error will also make other parts of the mounts more difficult.
other than the above mentioned pulley offset, the LS alternator mount fit the alternator almost perfect, and the fitup of the 60v6 alternator mount also looked very promising, however, some of my measurements were not quite right. as you can see in the above picture, with the mounting plate bolted to the alternator, it's not meeting the rest of the assembly square. between this, and the pulley offset issue, I'm probably going to completely redraw this mount.
"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."