sektor -
First, let me say that I'm no expert in this and with all the other experts/professionals on this forum, you'll probably get better advice.
I recently added in-walls to my family room because of similar restraints - lack of room due to room configuration. I put the R-5800 in front and R-5650 as rears. Now, I'm not an audiophile by any means ($ mainly), but they sound awesome. I've had many positive comments about how well they sound. I think with the right power driving them, they should sound fine. No doubt you'll lose some of the "directness" of the speaker, but for home theater, having a good center channel facing you, I think it will work fine, as the R&L fronts serve more as ambience in a movie.
Just my .02 - I'm sure others will have better suggestions/feedback.