I finally have regular access to a computer other than my phone!
I'm certain that Big Chainring was right about these bikes being made by Superia. I found a muscle bike on ebay that really helped to confirm that. I posted some pics in the thread Show Us Your Belgian Bikes here:
http://www.bikeforums.net/classic-vi...-bikes-11.html

Superia has an interesting story:
1956 - Family Feud
This version seems a bit slanted though, I read somewhere else that the brother who owned Superia eventually bought out financially struggling Flandria and dissolved the Superia name. But that's about all I could find out about the history except for a photo here and there of a pro wearing a Superia jersey.

So now it looks like we can add Belgique to the list- thanks Juvela
Pan World, American Arrow, Rapidix, Montgomery Ward Elite, Belgique...

And- Oberthecat- please post some pics!