Nexus 7 dual-boot with android?
Solution 1:
Yes, it is possible. See this Video and follow the xda-developers thread linked there. In development.
Solution 2:
There is no way to do it with the current image but it has been requested. At UDS it was discussed in several sessions and requested by people but there are no current plans to implement it. Here's the bug that was opened where you can track any work that occurs.