Just a quick follow-up and thanks.
The new sensor arrived (isn't eBay fantastic) and after installing, the engine fired right up. I'm sure the new plugs, coil and battery didn't hurt (apart from my wallet).
A few lessons learned:
1) Follow the L-Jet diagnostic completely if your '82 on won't start.
2) The flywheel sensors can go bad at any time. In this case, I should have figured it out earlier because the computer was allowing the engine to crank freely, pump gas through the CSV etc, because it was just waiting for the sensor to find the point on the flywheel.
3) Separating the flywheel sensor from the metal block it's attached to can be a real pain. Mine was completely stuck and took a while to drill out and resurface the inside with a dremel and circular sandpaper attachment.
4) The inside of the sensor is pretty clever - it is a powerful magnet which is surrounded by a coil of copper wire. When the piece sticking out of the flywheel passes it, the resistance changes. Mine had signs of corrosion inside the sensor, which is probably why it failed.
5) There are a few sensors in that family, and I think the difference is only the length of the wire. I replaced mine based on the number on the sensor, which was 0261210001. I think you can use 0261210002 as well. I paid $44 on ebay (shipping included). The comparable part at International Auto is $108 not including shipping.
This board is the best. Thanks for all your help.
'82 Alfa Spider Veloce + '74 Fiat X1/9 + '10 Mazda RX-8 GT