PCB fabrication (low volume)

Kemp,

If you are planning on making single layer boards, you might want to consider obtaining, by any means, a CNC mill to etch your own boards.

Some interesting materials you could toy with called Pyralux and Kapton made by Dupont lets you make paper thin flexible circuits. The pictures below is of a single layer circuit examples:

An Arduino based Dev board on Kapton.

A simple header with LEDs on Kapton.

Cabe

The seeeduino flex-based arduino clone is NOT single sided; it has top and bottom track layers.

I have a CNC router for PCBs, and it's a bit iffy for modern fine-pitch circuits, even in single-sided modes.  The absolute spec on this beast (an LPKF) is something like 0.2mm tracks between 0.2mm spaces, if you have everything set up just perfecct, so 0.5mm pitch TQFP type things are on the very edges of possible (no soldermask without additionak effort)

You can buy an awful lot of group-purchase professionally made boards (ala Dorkboard, or Sparkfun, or etc) for the $5-$10k the mill will cost you.

I have used only chinnese pcb makers. Itead Studio are really cheap $12 for 10 boards of 5cmx5cm. The quality is ok. The bad side is that the shipping is awfully slow. My last board took almost a month to arrive from china.