Do we see the first GPU miners on that pool?
http://yac.ltcoin.net/hashrate explodes from yesterday 18MH/s to over 50 today
Top current round Hashrates
Rank nickname KH/s
1 qq724174 29928
2 QQ213378 913
3 darkhorse 791
It could be GPUs, but most likely it's someone with a server farm, AWS or similar.
The GPU implementation seems quite complicated to optimise and these numbers are achievable with enough servers.