Well, Firefox Mobile does sync bookmarks & history. But I think most mobile devices are still limited enough you can't really run a full-featured browser and get good performance -- thus the current lack of a direct Chrome port on Android.[1]

Trying to 'sync' extensions between two radically different apps probably isn't worth the headaches it would cause... even an auto-suggest would probably mess up enough to be annoying.

[1] And, despite this article's headline, that doesn't seem to have been announced.