Well, lets see. The Mk VII's and Mk VIII's are pretty popular. The LS's are too. Then there's the Continentials and Signature Series. You've already covered the older models, but if it gets too large, that could be split out. I'm sure I've left someone's favorite model out, so please add the ones I can't remember right now.
As I posted to the SysAdmin a few minutes ago, there are a lot of enthusiastic Town Car and Continental owners who would probably add their two cents now and then. As shown in my sig, you have covered my other FMC vehicles quite well so it's a good job so far.