I just (last night) got a set of these from the widow of a cabinet maker.
I think the 'Wood River' brand at Woodcraft is the same thing.
Maybe the parts are interchangable.

 

Taff, I have these and really use the heck out of them.

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/boomer_clamp.html

 

I have 2 of each of their 2', 4' and 8' guides. I fortunately was able to get extra small parts for them before they went out of business.
I remember talking with owner a couple of years back and he was hinting at closing down because of the chinese knock offs appearing. It is a shame to see another high quality made in the USA small business close.

 

Just found this page and am so soooo sad. I have their 48" and was just looking to get another one to help cut down some plywood.

It's a darn shame. I'm happy to pay good price for good products, and this was a good product.

 

I am amazed that it has been so long since I brought this up and I want to thank all of you who offered their advise and direction. I am also kicking myself for my own (no other word for it) "stupidity". It took a while but, finally, the light went on (it takes a while nowadays) - I was holding a piece of mahogany when I realized I had the solution to my problem in my hand. I fashioned a new handle from the mahogany, pinned it in place and the problem was solved. I made a few extra handles in readiness for others breaking (doesn't happen when you're ready for it) and I am good to go.