Room and size restrictions sounds cool, because although youre limited no-one can dictate the shape, size, setting or different layers in one room..

something along those lines sounds good

Hmm, so it's agreed that the contest obviously has to be simple to ensure success. I also concur with Reno that HLDM is really the only viable platform to map for.

As for restrictions... I think something along the lines of 5 textures (no more than 1 mb of texture memory?) and the map be a one-room, large central arena. Keeping it simple while allowing for some nice setpieces. Should gameplay gimmicks be allowed? (i.e. a train that moves all around the level)

Not sure about your mish-mash idea Lep, how will you know its all from actual disused maps? To avoid cheating that is.

It would be good if you could do a GMDM2 style mini-mod, but I'm not sure if that would work. It would seriously disadvantage the non-coders among us.

I like the idea of working from a pre-defined set of resources (textures, sounds, mapmodels etc.), you suppose we could combine that with CJs idea?

EDIT: I just had an idea. How about, each map must have a "cool" effect in it, eg. shiny floor?

All this talking about only 5 textures lets me remember the screenshots from HL2 alpha level builds. How about... only orange (or blue, whatever) test textures? One orange raster texture, a masked ladder texture, a railing texture and one or two light textures... that makes 5 exactly and ensures noone has an edge over the other with his/her textures... Then you will have to impress the player pure with architecture and lighting only...