If you're in US, it'll be coming UPS not USPS. Ah, my bad; thanks. Still don't have a confirmation, but at least I won't be looking for the wrong shipper.
My order had 15 line items, and I'm in the U.S. I haven't gotten a shipment notification from either the USPS or Reaper, and according to comments on the Kickstarter page, emails aren't being responded to until after everything is shipped; I sent them an email anyway, and the wait, while understandable, is still a little bit frustrating.