Just hunting around for a tiny 32-bit MCU in a simple TSSOP package and I came across both ARM M0+ and modern ones ones based on the M-CORE, remember that? Well C-SKY copied the M-CORE ISA into their chips and I can pick up a fully loaded 32-bit MCU for 18 cents! Fully loaded means all the usual peripherals such as dual UARTS, I2C, 12-bit A/D etc and also comes with 32k Flash and 2k RAM. The ARM chips are much more expensive at 30 cents
This sure beats the cheap 8-bit micros which you can get for as low as 3 cents but don't have the punch these do. Maybe I might write a little Forth for the M-CORE just so I can drop the chip in anywhere and develop the code for it interactively but also be able to run scripts from a host MCU (wonder which one that would be....?).
I also have the less interesting ARM option too. But all this for another day once I have all my hardware in production.