If you don't mind the counterparty risk (such as if you are not insisting on a wallet that has you keep your private keys at your end instead of on their server) then Ripple is maybe about the closest thing to it right now.
You'd have IOUs for many different currencies in your Ripple account, basically, and go through gateways to turn them back into actual coins on actual blockchains.
-MarkM-
I actually not worry about the counterparts risk at the moment, since those coins other than bitcoin hav't took off yet and worth not much.You'd have IOUs for many different currencies in your Ripple account, basically, and go through gateways to turn them back into actual coins on actual blockchains.
-MarkM-
If some coin finally showing signs of success, then I can move out to use my own wallet.
But do not want to have to many "block chain" to deal with.
