[...] even i was unable to move the micro-desktop board (which is
only 4in x 4.5in) forward because i had designed it as a 4-layer PCB -
costs are around $400 for qty 5 4-layer prototype boards on a 3 week
turnaround  by complete contrast, a 7-day turnaround for qty 5 2-layer
prototype (bare copper) boards with larger vias is around $40 for qty
2, and around $100 for qty 5.