I put the smooth idler wheel kits and buildlog.net arduino-compatible stepper shields (bare PCBs and complete kits) back on sale.  They will be shipped on the 26th of February.  I also listed the 3/4″ and 1″ spacers that have been out of stock for a while, but they will ship at the end of the month.  Still working on the V-wheels and eccentric spacers.