I've got a 4S Turnigy Nano-tech that has a charge rate of 10C. Just have to put together a charging system big enough to try it out

But yea, asking for a lipo that can take a 20A charge rate is pointless unless you provide the mah in question. Almost any 8000Mah+ 2S lipo can take 20A's but a 4000Mah one would be a rare find.....and if we're talking more cells, then your charging system would come into play also.