Ebay for sideart. But you have to wait for the perfect one.
I haven't seen anyone who carries a huge supply. If a company has some, it seems like its just what they found in the back.
There are a few companies that make reconstructions. They seem to look nice, but thats a picture over the net. But they can be 150 bucks or more.
As for buttons.
www.videoconnect.com, bob roberts (look at links), happs has a special on horizontal buttons now for 99c (but I hate that you have to take off the microswitch to take them off).