Works Connection once made frame guards for the XR650R but discontinued them after a while.  They pop up used once in a while if you keep your eyes opened. They looked like this:

The only manufacturer still making a quality frame guard is BB Aluminum. They look like this:

They also manufacture some very high quality skid plates, chain guards, muffler inserts, and speedo eliminator kits.

If you live in the United Kingdom the BB Aluminum products can be purchased through Demon MX - they are the UK importer.

Additionally, guards can be made easily at home by cutting thing aluminum or chrome diamond plate – then affixing it to the frame either through a couple small bolts (drill and tap holes) or with some 3M double sided tape or glue.