Along with announcing the Wave Bird, Nintendo stated that they were going to release a Rechargeable Battery for the GBA, yet they never have.
Therefore, what is the best un-official rechargeable battery currently available for the GBA (not SP)? I don't need something that's "hunking-out" at the back, like my previous one but something more like:
Preferbly, I'd want something to match my transparent GBA.
P.S., I'm aware of the Nintendo AC Adaptor that's available, but does not act as a rechargeable battery.