Todd
It is possible, the side burner is modular, which means that you could remove the LH SS work surface and screw in the side burner. You would need to lift off the cast aluminium box section and put the gass hose behind, you would need the tee piece adaptor for the gas lines.
The problem is that Weber will not sell you those items to carry out the modification, a service tech would need to do it if you could con one. It's not rocket science but the parts availability makes it near impossible.
Regards