Yeah, I really love hasu's controller.
I haven't really had time to experiment with keymappings other than the SpaceFN layout which was included with the firmware zip. So I'm pretty much using the default HHKB layout, except that I'm still having trouble hitting Home/End when I need them.
For Bluetooth, I'm using a Sparkfun battery that hasu recommended. Battery life has been pretty good so far, although I haven't really been keeping tabs since I use my laptop for a couple of hours at a time here and there. hasu mentioned about 8 hours, I think, but it seems to be longer than that?
I would love an alu case, but my main usage for an HHKB is plunking it down on top of a laptop, and an alu case would probably be too unwieldy and might scratch up my laptop. Also, I don't know about Bluetooth's limitations, but I remember GON added BT support to his boards, but he mentioned BT would only work with his plastic cases and not the metal ones.
Enviro is one of my favorites.
I should be getting an Eyeland T soon to go with this one.