Energizer NiMH go up to 2500mAh (at the usual 1.2V for NiMH):
http://data.energizer.com/PDFs/nh15-2500.pdf
Duracell go up to 2650mAh:
Products: Rechargeable
Varta are already at 2700mAh:
VARTA - Power Accu AA 2700 mAh
FWIW, all my rechargables are Varta, they make some quality stuff.