Unfortunately there are no other good coreboot boards which allow a similar modification to be done at this point.
There is Asus M2V-MX SE with DIP SPI flash. It works nearly fine, the last problem is with powernow-k8 - frequency change of CPU has some grave problems.
Otherwise everything else works and it is socket Am2 board. I'm working on VGA console, now VGA works with openchrome drivers.
Rudolf