where To Buy Precision Resistors Fast

Mouser ships from Texas, so their shipping should be faster and maybe cheaper than Digi-Key, which ships from Minnesota.

There's also BGmicro.com in Texas, a great place to check for all sorts of electronic surplus.

I don't know about 0.1% metal film through hole. The finest I've bought were only 1%. Surface mount, yes 0.1% thin-film carbon resistors - laser trimmed - I use these usually in the < 300 milli-ohm range for current sensing on high power LED drivers

Digikey or Mouser would be my recommendation for the resistors. Digikey carries a couple of lines of precision resistors, 1% to 5% in certain lines.

The stepped attenuator/switch with 12 steps may be difficult as most have more positions. I have a Russian stepped attenuator on the bench, a monster piece, probably from some military application. It's way too big for anything you have in mind.

OK, found a single deck 12 position switch from Goldpoint. You'll have to contact them about the shipping window. Their products are first class.