If anyone is looking for Racks (Top or Side) for the Suzuki GS500 E or F, I just found these from Fehling (Germany). (They also make an Engine Guard for the GS500E). A quick email to them and I got a quote for shipping from their factory of roughly 116 Euros for the Top Rack, and 147 Euros for the Side Racks plus shipping (to the USA that was about another 40 Euros).
Here's the link to their Suzuki catalog page with current prices:
(https://www.fehling.de/index.php?lang=eng&content=preise&markenid=10)
I don't have a photo, but here's a diagram I "borrowed" and annotated from one of their Czech vendor's websites. You may be able to find an existing distributor for them in your country.