So it looks like we have Pere potentially mentoring for Tux Paint, and Brendan being available for Tux Math/Tux Typing/t4k_common, hopefully including any new mobile games written from scratch.
That gives us the potential to apply for two slots for GSoC. I'm not sure if the application will be successful without more participation, but it doesn't hurt to try.
Keep any ideas coming into this thread. I can try to get the ideas page into shape in the next day or so. We also may need to try to get a "sponsoring" organization identified.