re: switches
there was recently a group buy for plate mount switches, and i'm guessing the forum will be awash with them in a month or so, but the poker will probably feel best with pcb mount switches, which aren't as common around here. you might want to ping the_ed, as he usually has a large stock of pcb-mount switches. note that he gets his from the same place you would probably look for cheap ones -- many old cherry boards used pcb mount switches and can be found for less than the switches would cost new.
re: caps
any filco-compatible cherry MX keycap set will fit the poker. this includes the KBC sets that feng and qtan sell, as well as the PBT sets that imsto is selling right now. this also includes the signature plastics doubleshot sets that are being ordered in the group buy forums. order a basic 87 or 104-key set, and everything will fit fine on the poker. note that the one thing to watch out for is that not all sets can be mixed and matched. KBC keys do not have the same profile keys as signature plastics.
alternatively, i have a used ABS set from a poker for sale in my classifieds thread, lol
also, i'm still looking for pcbs folks