I am using 1.27b (or whatever with the newest patch)... the 1.6 modpack from Mephisto et al. and on High Difficulty and with a Medium Bonus. I set the computer to low # of opponents but handpick: Darlocks, Earth Alliance, Narn, Sergetti, Torons, Xichung - these are all on 5000 racial points and I have made sure all the points are used up for them. Note: I too am using all 5000 (3000 for emotionless), which makes a difference since I knew I had given myself a bit of a 'soft' start. I was playing Rock/Carbon Dioxide and only had about 5 non-domed, but still a pretty strong start.
The XiChung kicked my butt (I played it out today) and I hope the next game offers the same challenge.
Jason2