You can possibly contact pioneer directly, though, they no longer manufacturer panels. I am guessing this will be fairly cost prohibitive due to dwindiling panel supply
For General Service & Support
In terms of replacing your existing TV, i'd very highly recommend the Panasonic VT series panels. They are hands down, the second best panel to the now discontinued Pioneer KURO. You can pick up a 50" VT-25 for about 1500. I currently own a Pioneer PRO-1130, and a 58 VT-25, and absolutely LOVE both. I still think the Pioneer's colors are a bit more accurate in the default Pure mode VS the THX mode on the Panasonic, but the black levels on the panasonic are an improvement.