As Amazon has sharply discounted several sizes of Pelican Cases.
I'm figuring that the Pelican 1650 will fit a PowerGenius XL and a second Pelican 1650 would hold a Flex-6600M with enough space for the needed accessories. As I already have my Portable Antennas, Feedline and cabling in a soft ex-Military case I'm not thinking of going larger.
Quick heads up that the offer is today only, and a quick check elsewhere on the Internet does seem to be a good price, especially with Amazon Prime picking up the shipping.
Also with the size of the PowerGenius XL's matching Antenna Coupler/Tuner presently unknown/unconfirmed, there is no guarantee that there will be enough room in the Pelican 1650 holding a Flex-6600M to accommodate the tuner as well.