One resource you can use to try and find a mobo to match your needs is
MOBOT at motherboards.org. It's a mobo database, check it out, very useful.
Did a quick search myself and came across the
ASRock 775Dual-VSTA as well as the
ASRock 775Dual-915GV. The biggest difference between the two being the 775Dual-VSTA uses the Via PT880Pro chipset and the 775Dual-915GV uses the Intel 915 chipset. Out of the two, I would probably go with the 915GV. A number of people have posted with success stories about the ASRock Skt939 AGP/PCIe mobos.
Aside from ASRock, you've got choices from Foxconn, ECS, ABit, Gigabyte, and MSI. More mobos out there than I expected...how many you can actually buy may be another story.
Good luck!