I have an Osburn 2200 insert in a fireplace and love it. I am building a new fireplace in a family room for a second unit. What I would love to do is instead of building a full fireplace, and putting a liner in the flue, is to build a fireplace sized box out of masonry (firebrick + regular brick for an 8" wall) and put an 8" reinforced concrete cap on this (30" off of the masonry floor). I would put an HT wood stove chimney in the back, with the thimble throught the back wall. The benefits are: 1. With an HT chimney out the back (into my garage), I can clean the chimney from the bottom (using the "T"). 2. I get a better venting system for this unit 3. I can more easily make a recessed box in the wall above this (out of brick) for a plasma television. Now, if I was placing a wood stove in this alcove, I would have no concerns, as there are no combustables anywhere near the unit; however, with the insert, the "clearances to combustables" are not given. Rationally, I am confident they are the same, but the instructions say that the unit must be installed in a fireplace. The walls of the masonry box are identical to a fireplace, only the cap is different. I would probably place fiberglass bats on top of the concrete cap. Are my ideas reasonable? or should I go ahead and build the full masonry fireplace (I have not found one that is big enough to hold the insert AND is rated for an insert. If I build a full fireplace, any thoughts on whether it is reasonable to build a recessed cavity (say 8" deep or so) right above it for a plasma screen? My thoughts are that the recess will help with the heat.