Seen them on ebay, rare spares, sparecity but they charge about $45-$70 per door. Wreckers are your best bet if you want them cheap but always a down side to second hand
I was told by a bloke recently that you can get compatible rubber seals for the doors from clark rubber. I have not had a chance to check this out yet.
There's a few places like Clark Rubber where you can buy the pinch weld with rubber for the body side door seals. Not sure if the fit is any good though. EBay might be worth a look.
Clark Rubber only have VB - VL door seals.
Rarespares is probably the best bet. Found they were the easiest to install of the aftermarket seals.
Only problem is they only come in the one grey color.