I am at the moment testing the GingerVillain V0.9 ROM for HTC Desire. Beside of being a stable Android 2.3 aka Gingerbread ROM, it gives me good speed and the best battery results I ever had on my HTC Desire.
I will add my Softbank mods to this ROM and test for some days. If it keeps its promises, I will publish the ROM here.
Here you can see my battery consumption of today, with the GingerVillain 0.9:
And of course the ROM will have the usual Softbank Japan mods and my small changes to the notification screen and battery. Currently testing a battery icon with transparent %.