Asrock appears to be still making 939 motherboards. I have found a pair of Asrock m-ATX boards, one featuring the 785G + SB710 chipsets with integrated ATI4200 graphics and the other with integrated Nvidia 7050 graphics. The AMD one looks much better quality. Unfortunately they are £57 and £58 each, which for a outdated socket is a ridiculous price.
If you are still interested the boards are:-
Asrock 939A785GMH/128M 939 AMD 785G+SB710 MicroATX RAID Gigabit LAN Motherboard
Asrock 939N68PV-GLAN 939 NVIDIA GeForce 7050+nForce 630A MCP MicroATX RAID Gigabit LAN Motherboard
If you search the names as above you should find them.
Personally i would save some money up and build a new budget AM2/3 rig.