I've completed a 40x40 building that can be played in UFO using Scott Jones' XComUtil.
You can see a picture of it here and there's also some combat screenshots here.
You'll need XComUtil's latest version (9.60 Beta) to run it since it has the specific features created by Scott to use Large Buildings. You can download XComUtil here.
To download the HWP simply go to my Area 51 page (link on the sig). Have fun

Edited by Hobbes, 23 July 2004 - 12:46 PM.