Originally Posted by
runningshoes
The only shoe I know of that fits your requirement is the Nike Free line which allows the back heel portion to fold. I have not run with the Free so can't recommend it personally. The other option is to roll stuff in the shoes (running shorts, socks, etc.) which saves some space.
I roll stuffs inside my shoes as well, it gives me additional spaces. You can do this instead of buying a new pair of running shoes.