I oughta look around the Recent Builds subforum a bit more then. Be sure to post a sample table entry so we know how to get it to work, please.
The 10/28 build in the recent builds forum should have it, but that's the latest Xt-based build that was publicly announced.
As far as using it goes, it's exactly the same as using it in the mission file. For instance, I use this tbm to have different textures on the Leviathan and Lilith:
#Ship Classes
$Name: GTC Leviathan
+nocreate
$Texture Replace:
+old: fenris-htl
+new: levy-htl
$Name: SC Lilith
+nocreate
$Texture Replace:
+old: cruiser03-03a
+new: cruiser03x-03a
+old: cruiser03-01a
+new: cruiser03x-01a
#End
And that's it. It will use the same POFs, just change the textures. And you can still use texture replacement in a mission as normal too. It will just get added to the top of anything you specify in the ship entries.