It looks like ExpressPCB only saves to their proprietary format.
You can do it in EAGLE. Just start up the board editor and place "packages" rather than devices, connect pads with the "signal" wire (or not, I guess) and lay down tracks.It's a really bad idea, IMO. There is tremendous value to the redundant error checking you get by having the tools check both the schematic AND the board, AND making sure they agree.
What does the ICSP header connect to? Just pads? Or to certain pins?Once you connect to pins, you're better off with a schematic.
maybe a pad for a 1uF cap.
Why the 50mil spacing? Just curious.
DipTrace also allows you to create/route a PCB without a schematic. And it has tons of landing patterns, so you don't have to create your own components for the most part.