I've got a ThML book importer written. There's a screenshot of BibleTime with two books produced simply by running it on a pair of ThML files at http://www.chiasma.org/~chrislit/bible/bt-genbook2.jpg .
This adds about a hundred new books that we can use, virtually immediately. And as new ThML books are added to CCEL (or old books are converted to ThML) those can also be used immediately. As a bonus, the importer is written in C. So it can be compiled and distributed to users (unlike the Perl scripts I use for most of my converters). And it will be easy to integrate into other programs, such as InstallMgr--so that we can have it download directly from CCEL & generate the book on the fly. --Chris