My situation:
I have a yard that is a horrible combination of bedrock limestone and very thin layers of heavily compacted clay. Crab grass has pretty much taken it over. There is no topsoil. I'd like the build some 6-8 inch high raised beds with compacted gravel paths between them.

The ground is not even close to level and wood is not an option for several reasons. (I've actually built some and tried it.)

What I'm hoping I can do:
Compact gravel above ground (leveled, of course) to serve as the path and the base for the bed walls. Build the walls 4-6 inches high filling with soil as I go.

In my head it's stacked flagstone with the base pieces being 2-3 inches thick and then pieces getting thinner.

It's my hope that since the walls are so low I can get away with the footer being above ground. We do get a lot of rain, but not many hard freezes and very little snow.

If this isn't advisable, is there anyway I can build garden beds up without having to dig or drive stakes?