Anyone know how to have Abe show top wallet balances? If not already built in, how could I query the mysql DB for this info?
No, Abe does not have this feature built in, and the addresses are not store in the database.
What you have is the public keys. So the way to go would be to query the database for all the public keys, transform the public keys to the network address, then ask Abe to give you the balance for that specific address.
You do that in a loop and then show the results with descending by top address