Hard tonneau cover as storage area, need ideas

I have a Undercover hard top tonneau cover on my DCSB. I just installed a Frontrunner roof rack where I plan on putting a RTT. I do a lot of activities that fill the truck bed and am wondering about storing extra fuel and off-roading type equipment in a hard case or storage bag ontop of the cover without buying an expensive rack system. Has anyone done any homemade attachment/storage systems? I'd like your thoughts.

It could be as simple as drilling eyelets to use as tie downs, or I was thinking about buying a cheap roof basket off of Amazon and bolting it straight to the cover. I am thinking it would only be for 100-150 pounds total kept near the edges so as not to break the cover.

 

Throw an old 4runner rack on there mate