It took a while but I finally got the bike running again and can finish this thread. I don't think that I'd do it again like this but it works and I'm pleased.
I did some research and got indications that a fan switch from a Geo Metro, 3-cylinder (1.0L) matched the threads and temp rating. I couldn't get one locally so I found the part on RockAuto.com
for $8.23 + $6.29 shipping. Click the Part Number Search
tab and put in the mfg. and number.
1994 Geo Metro 1.0L 993cc 61cid L3 TBI
Radiator Fan Temperature Switch. Mfg: Beck/Arnley
, Part# 2011614
(I see they're offering the closeout switches even cheaper now.)
So, here's the Geo switch (on the left) and the stock GL1100 switch.
The Geo switch does not have the long probe that goes into the thermo housing. It also has a different connector. So I fashioned a pigtail from 4 inches of wire and bullet connectors.
I shrink-wrapped it all and stole a black rubber foot off grandpa's cane and here's the finished product.
I couldn't find any specs on what wire is which so I just chose one side to be green and one side to be white/red (I think those were the colors). Then I figured if it didn't work I could switch them.
Amazingly, it works! Fan comes on when it should and all is well.UPDATE:
Though this switch worked I ended up replacing it with an OEM switch (about $80) when I later replaced the water pump and head gaskets.