Yes, I do have a Bosch wideband installed in my car. That signal is read by an AEM gauge, which sends its linear 0-5v signal to this custom board:
which emulates a narrowband sensor, and lets me pick two different AFRs that I can cycle between via an external switch.
If I ever exhaust the 2K flash of the Tiny, I can move up to an ATMega162 fairly easily. I'm not using assembly as means to get the program to fit on a Tiny. I'd still use assembly on a 162. Compared to x86 asm, the AVRs are a pleasure.