I'm going to say from experience that its impossible to have a frame around and not buy components for it(I got a good pric on a tri frame last August). But along those same lines, I got a whole bike together with some decent specs (vision aero and base bar, FSA Gossamer crank, Selle Italia seat, Shimano 600 components, and some basic training wheels) for $400. Mind you, people sell stuff for a lot cheaper between October and December than January and march so it isn't exactly a buyers market right now.
My point is, if you have a frame you'll want a bike. You can get a bike put together for cheap if you're patient. Otherwise, get the frame and do some thinking, at least then you'll have the frame for when it drives you crazy thinking about the bike you could have. I'll be posting pictures of my new bike sooner or later.