recently made my own luggage racks to which i attached a pair of cheapie bags i got off ebay and a GIVI ripoff top case gotten from JCW. made the brackets from cold rolled 1/2" tube steel. after these pics, i had them powdercoated flat black to match the bike. it comes apart at the top under the topcase bracket (as in each side is its own seperate unit). i designed the whole thing so that from fully loaded cases locked and riding can be removed completely in less than 5 mins with a 4MM allen, 13mm wrench and 9/16" wrench. put all stainless hardware on it and have load tested it for 300lbs on the top, the side bags are limited to the rigidity of the walls of the case. the ones i have are kinda flimsy plastic so i dont go crazy with them, but have put over 60lbs in each of them without worry. i got tired of trying to figure out how long it would take me to save up for system cases. i also made it so i can easily fit larger side bags on (which i am looking into right now, might just make some out of sheet steel). used them for many trips this summer and they work out great and allow a passenger (provided she isnt a large girl) without any interference at all. i also added black handles to the tops of the side cases. the side bags must be opened to pull the pins out to take them off. they are lockable so nothing can be removed without the keys. the side bags, top case, tube steel, hardware, everything except welding wire and such like that cost me about 240$ and probably 30-40 hours worth of work. im very happy with how they came out except for a couple small snags. comments and questions are welcome, can even take more pictures if wanted. wanted to help encourage everyone to go out and try to make your own stuff, its not that tough (given, i am a fabricator by trade, but these are simple) and is very rewarding. riders stop and ask me where i got that luggage all the time. enjoy!
Side bags, I believe, need to be bigger for them to be really useful.
Besides this I admire the kind of work you've done.
And I agree. BMW's bags are pretty expensive.