According to some recent sightings, MicroMaster Railbots (first appearing late 2005) are resurfacing in their original exclusive retailer (KBToys) and CVS pharmacies.  Not enough sighting data to really tell, but it looks like they're appearing in east coast US.  Coincidentally, I was just going through our toy database last night, and noticed I was missing another MicroMaster group, namely construction vehicles which originally came out at the same time.  Perhaps these are being found too?  Check it out, and keep the sightings comin'.