I am using SBC. you can pic them up pretty cheap (<$100 in most cases), and they are plenty powerful enough to run the linux stuff. Typically they have 1 PCI slot and some built in's. ALWAYS they have built in NIC. some have parallel either as a connector or actual DB25. They are starting to move away from PATA and only have SATA support.

My current project has 4G SSHDD and 1G ram. It is fan cooled, but even fanless can be had.

I would also like to be ablu to use a laptop instead of a dedicated SBC. This just for the ease of development. As you know, laptops are now having less and less connectivity.