Mike,

0.004" tracks are not unusual. 0.005" vias are not unheard of, though I admit I've never seen a hole that small in a single-sided board. What do you mean by ridiculously small?

If you can't build a board in your bathroom that has .010" traces, then you need to refine your technique, though that's probably about as small as you can go without lots of specialized equipment. Half-millimeter (~.020")traces are not too large for use in conjunction with the typical "floppy disk drive header" used on Pentium motherboards. You should be able to manage those.

Have you looked at the arrangement used by the New Micros people on their NMIY-0031 board?

With a single-sided board, it's anybody's guess how you'll avoid lots of wire jumpers.

RE