Is there a wallet for different cryptocurrencies
You can use UFASoft Coin. Which is a multi currency client and miner. Also it's open source.

The supported currencies are.


Bitcoin - BTC
Bitcoin-testnet
Namecoin - NMC
Litecoin - LTC
PPCoin - PPC
NovaCoin - NVC
TerraCoin - TRC


This will essentially keep all your wallets in one application, so no more have 6 different wallets and clients. Then forgetting to start certain ones.

Just a side note regarding the performance of mining directly from the program: I have found it to be slower, around 10-30% slower than other miners.