Hyundai maybe? They've been slowly working hard and have now caught up and even beaten their Japanese competitors in Honda and Toyota. They may not want to have a team of their own but come in with major backing like BMW did with Williams. Williams has the know how, the technical support staff and had a pretty decent car this year. I'm sure with major cash injection they can once again populate the sharp end of the grid consistently
They have the money, but the performance of the Korean GP could make them shudder. Ironically, if Hyundai got involved it would probably do wonders for F1 in Korea.