A REALLY accurate clock.

[Mike, K8LH]

I understand what you're saying and I agree (generally) with your premises but you shouldn't dismiss or exclude the 12F and 16F "enhanced" midrange devices. They're pretty potent with a 32-MHz clock, linear RAM address mapping, an interesting assortment of peripherals (some not found on 'legacy' 18F devices), and an excellent price/performance ratio. In fact, I can think of one case where the new FVR (fixed voltage reference) module is found on some 18F "K" series devices and on some 12F/16F "enhanced" devices, but the "K" series devices can't use the FVR output as the ADC +vref input as can be done on the 12F/16F "enhanced" devices.