Still doesn't help out answering the questions put forth. is there currently a way to mine other bitchains at the same time, not supported by p2pool such as geistgeld and liquidcoin?
Hmm, there might be. Right now you can mine BTC and NMC at the same time, it's called "merged mining".
It might be possible with those others you mentioned, it would be a feature of the pool. The pool will give you the work. One of the pools I used had a lot of different chains you could mine against, and it would even automatically give you different blockchain work depending on which had the best profitability for you based on your mhashes, current difficulty, etc. I forget what that one was called.
[quick check]
Ah, it was called Coinotron. What you want is merged mining. You just need a pool that supports the blockchains you want.