To answer your questions, yes all model packs and store models are compatable with X10, but for some of the newer models, you may have to tweak the entity information. There are some tutorials that you should be able to find with help on getting these models working. I know that science boy did one recently on getting Model pack 52 to work. Here is that link:
http://forum.thegamecreators.com/?m=forum_view&t=179216&b=33
Here is another thread that has some information on getting the newer packs to work:
http://forum.thegamecreators.com/?m=forum_view&t=178989&b=33
Mystic-Mod: Putting the fear back into sliced bread since 4th May 2010