Check out Legacy Audio's in-wall speaker selection (Silhouette model), I've heard them a couple of times over the years and they pack alot of near full-range performance (42Hz-28Khz I think) into a well-built and builder-friendly. Induction Dynamics also has a large speaker line of quality products that sound great, at least two of them are in-wall designs, the largest of which is a 4-way in-wall tower equivalent....
