Micro lipo 2S

I just received my WLToys 284131 (1/28 drifter/touring). Had a blast with the first battery, impressed that the 450mAh rated 2S lasted about 10-15min. But that thing is small. Smaller than my Tinyhawk batteries.

Anyone know of any good 2S lipos smaller than 15mm x 18mm x ~50mm?