well if u can code and invest time, then contact blender.org and ask to work on the gameengine code with kester(the GE coder)
this would be great!
the major issue in blender is the lighting (it don’t support lightmaps yet, but that will come), it’s hard to get good results.
-go with vertex color => quite ugly
-go with radiosity => a lot of faces (see the architectural demo at blender3d.org)
-go with “texture baking” (not in blender) => HUGE texture load
i’ve not seen all the things done in the blender gameengine, but as far as i know, my demo is one of the best, graphically-wise http://www.elysiun.com/forum/viewtopic.php?t=29815&highlight=rusted
as for others options, they are several opensource 3D engines, but none have a graphical interface like blender, so u need to code your entire game (so if you are nor a programmer, that’s useless)
the best would be to stick with blender until “multitexturing” comes out or go for the lite version of quest3d (89$) which is not too expensive.
there is a “community game project” starting to shape, u could contribute.
hope it helps