For a couple of years now, I've got two pairs of first generation Time pedals in good condition that I've been meaning to put to use. I can get the cleats readily enough (now that I finally know what I'm looking for). Of course the problem is that the two part/four bolt cleats don't fit on standard Look-compatible shoes without the adapter plates.

Anyone know of a source for those plates?

Try searching "Sidi Road Shoe Adapter Plate for Time". They were designed for use on their older shoes but you may be able to jimmy them onto the sole of your shoes.

I think the adapters that come with every Speedplay cleat should work. I have a pair of Time compatible shoes, I omit the adapter plate when using these with Speedplay cleats. I should have a bunch of old ones in a box somewhere...