Yep, I ran into the same problem recently. I had purchased a 42" rear projection samsung and it seemed that every entertainment center was designed either for the giant screens which would leave huge gaps between the TV and the side cabinets, or for much smaller 4:3 ratio TVs. This is what I purchased which also has the benifit of no doors over the components.
http://www.brownstreet.com/proddetail.php?prod=5524_Newmarket_Media_Center&cat=62I was a little nervous, because we couldn't find a local store that had the cabinet in stock, so we purchased it sight unseen. I'm glad that we did though, it's a nice piece and I'm really impressed with the quality of the woodworking. If you'd like, I could post a picture of how it looks in my living room.