I have a Grizzly and wanted to splice two tracks. The kit only comes with one connector and it had a lot of flex to it anyway. I made my own connectors out of hard maple milled to fit the slots tight and drilled and tapped them for 1/4"-20 set screws with two on each side of the splice for each connector (8 total). It's pretty stiff.

I've bought several things from Tools Plus over the years. They often seem to have the best price on power tools and sometimes have it even cheaper at their Ebay store.