What a disappointment , thought this was going along the lines of “nice rackl”
They make lots of different ones, for different boxes. I only put a link to one. Have a search through them
They do identically styled ones which (with a bit of ingenuity) you can fit on the K1100LT top case.
I had a Givi top box and rack that looked very similar to that...
Not easy for me at moment as I am recovering from a broken leg. If I can get to it (got to find it first, mind you), I can send photographs and measured detail? Would that help?
Spotted these on eBay - not sure if it they would be suitable ?