not that i know of. there's a few that are popular w/in the community. sohailtech seems to be one that everyone knows.
I'm working on a few projects which we plan on making "big". one is mine and i'm the sole dev, the other one i'm working on is with a mod from this site, which is a unique custom-built rpg. both links can be found in my sig
I wouldn't know one off hand other than the Main x10Hosting site, but I'm sure a quick hunt through Alexa and such will turn up some pretty interesting results . I'll do that now and see what turns up.
I bet there are many popular sites hosted with x10hosting... its just that the jist of people who pay for the hosting, are too busy running a business of some sort, that they don't spend time "advertising" in the forums...but instead work on their site, and manage their whatever..they need to manage...to make some money...and increase unique clicks on the site.
There was one that I know of from a few years back but no longer hosted here. Also now and then you see some small sites on domains that grow a bit bigger and then either close or leave to another host (paid host).