Justin,
We had the discussion before and they are not wide enough. But if you check Ebay there are also panels sold in differnet sizes. As long as you keep the cables on these you can cut them in any shape. It is important that you seal the cut edges with a good tape to prevent damage by moisture.

Justin,
Try DigiKey for bigger panels. There are other places that do them too
try Mouser Electronics, RadioSpares (RS) in the UK etc.

For the small GTS panels I used All Electronic Corp who do a bunch of salvage/resale as well as new - they sometime have some interesting deals - all one time things though - a place to check out from time to time if you are a "tinkerer".

Bigger panels get expensive. Some come with multiple edge connections so you can slice them up into multiple useful pieces (saves $$).

Alan