We did... managed to just get them via OSU/Ticketmaster for $30/each (with fees). We didn't even bother going to our actual seats, just sat in the bottom row at the 300's. Lots of empty seats, unfortunately... but it meant we could move. So glad we made time to get away to the game!
I would venture to guess, there were 11,000-12,000 people? Out of that, there were 1-2,000 KU fans, maybe more.