Alrighty everyone… or rather, the eight or nine people who are interested in this project 
I’ve put together a preview pack. It’s fairly complete and I’d like for people to have a play with it, but NOT RELEASE MODS WITH IT OR REDISTRIBUTE THE FILES 
Things that are NOT included in this release are:
- The large corridor set
- A transition to cave (will be done, is essential for an underground dungeon
- Slave cages (for reasons as below)
- and the most important one… animated doors.
I haven’t made the doors usable yet, as I have no idea how to do it! There are a couple of load doors included in this pack but no animated ones – if anyone has any idea how to do them then please let me know, I’ve got models but no know-how 
It works very well indeed if you have a grid snap to 256 – the interior tiles’ dimensions are either 256 or 512, in general, or are centered to take advantage of the grid.
I would like, as it says in the readme, copious and merciless feedback.
If you would like me to send this preview pack to you, email me: jonesthebond at gmail dot com. If I send out the models to you, I’d appreciate a few comments on it somewhere, so I can make it better before I make a full release.
Anyway that was a lot of rambling. Cheers for all the help guys!