As a change from whining about CNC routers and ADSL, I thought I turn my attention to building a workspace for the computers/electronics hobbies.

What I want to build is an L shaped bench, each leg of the bench will be 2700mm, depth about 700mm. Material will be 25mm MDF (shouldn't really call it furniture in that case).
I had a single bench in Sydney (3600mm wide). For that one, I fixed a batten to the walls on three sides and had two supports cantilevered out from the brick wall to which they were dynabolted. This gave plenty of leg room without table legs getting in the way.
Problem with my current place is apart from having plaster walls, the real estate agent will go ballistic if I start drilling holes in the wall looking for studs!

Ideally, I'd like support only at the ends and at the back (against the wall) but I'm thinking that the top would sag without legs at the front.

Suggestions please!