I would stay away from a few brands like Apple and Bose from the start. These brands are not synonymous with sound quality and usually expensive throughout their product lines. I would tend to look at any electronics manufacturers (Sony, Phillips, Panasonic etc) to see if they have any cheap offerings (they probably won't sound that great). For a more expensive sound dock I would look at speaker manufacturers (Klipsch, B&W etc). I'm afraid what this would cost, it will probably sound halfway decent for what it is.
http://www.bowers-wilkins.com/display.aspx?infid=4360
