The latest x10 mini firmware news and releases from the XDA forums are as follows:
MiniCM7-2.1.5 – Gingerbread 2.3.7/CM7.1 unofficial port for the x10mini ‘The true CyanogenMod7 Experience!’ Note that the requirements for this now include an unlocked bootloader and the nAa kernel.
nAa-06 Custom Gingerbread kernel + CWM Recovery – You’ll need this for the above!
If you’re not up to date, or starting out from scratch try using the new flashtool.
If you’ve tested or use any of the firmware listed please give feedback to other users via the comments.