mining with one client on multiple mining pool Is it possible to mine on different mining pool using one client?

Ok, I know that this sounds ridiculous, but my thoughts are as follows: if I already calculated a lot of hashes for a work for one mining pool may be I will be able to use them for another mining pool. Has anyone thought of it?
The hashes generated by your miner is only usable for a unique set of transactions that your pool decided to include.  In addition each pool orders transactions differently and that too will affect the resulting hash.

Unless the pools cooperate and synchronize all the details of a given block (nonce, merkle tree, etc)  then any hash that is generated is useless to any other pool.