I'm assuming you're removing the floppy drive when going portable. I know you're removing the HD. IIRC, the rest of the Amiga will work fine without the -12v. In fact I'm not even sure it will need the +12 with the HD removed. The CF card should run on 3v or 5v IIRC. The only sticking point would be the voltage conversion through the IDE-CF adapter. It wil be expecting to see a +12 and -12v iirc. Bypass that though and you should be good to go.
I think this is your best bet. If you don't need the -12v, no point in hassling over it.
Buy.com and others have big sales on rechargeable batteries this holiday season. Charchers too. Some take 12-20 batteries at the same time. Start your shopping here:
Recharge lots of batteries at the same timeWho knows what "super quick" charging means from SONY?Where I find my deals for electronics like batteries
