Have accounts that have been inactive for a long time get their name changed to something else, so that the people can have said name after it fills up.

I would like a specific name, but all slots from 0001-9999 are filled for it. I suspect the majority of these accounts are inactive, so I think that after you're inactive for say 3 months, 6 months, a year, whatever, your name changed to an alternate name such as a few numbers, to minimize the number of inactive accounts taking up slots for names.