I think 1000 posts should be the point at which not only can you pick from all the avatars, but also get to use a custom user name. I mean only about 220 something out of the over 6000 users on this site have over 1000 posts, am i right? I mean 4000 seems a little steep in my opinion.
Along the same lines i think custom avatars should be given at 2000, for the same reasons.
Just wanted to share my opinion. Thanks Jim