I know you mentioned one day building your own system for adding avatars, but I thought of a cute new idea for default ones in the meantime.
I thought it might be cute to have our (default) avs be an icon of what our current bee level is. Right now, mine would be an olive. But (goes off to check) 19 posts from now, when I reach cherry, it would turn to a cherry icon.
I'm in no way tech-y, so I don't know how dificult it would be to implement something like this, but figured I'd throw it out there.