Motorola 603 processor XPC603PRX180RE on IC-China's ebay store. Has three. US $5.95 BIN and flat $6 shipping.

Possibilities: 166MHz module from a 1400 (which were downclocked 180s), or 180MHz module from a 2400 or 3400? Or the rare 180MHz 1400 upgrade?

This image of a NuPower 183 MHz CPU from the link above certainly suggests it's for a 1400.