Hi folks, just thought I'd share an idea I had with you.
Let me start by saying that this is not a "leave no trace" friendly way to hang... but it ain't bad either...
I run a hunting and fishing forum (huntandfishnj.com) and one of our members posted this one day in our trapping subforum. If you combine this technique with two standing posts (two inverted Vs / Bipods) you could hang your hammock anywhere the soil was sturdy - no massive tent spikes required.
Note: I've never tried this with a hammock - but I'd bet it'd work just great.