It's been so long since I have been here my account was locked due to password leak...

However, I came here today looking for the same kind of info as you. Let me share with you some links I found earlier in my search:
https://en.bitcoin.it/wiki/Software#Mining_Pool_Servers_.28backend.29

https://bitcointalk.org/index.php?topic=61731.0

https://gitorious.org/bitcoin/eloipool?p=bitcoin:eloipool.git;a=summary

https://github.com/bonesoul/CoiniumServ

For me I wish and hope I can use a Python based server, however I have spent most of my recent time in C# I have not even started evaluating which of these projects are working, but I will get there.