I pledged for the R-10 UAir quad on Kickstarter some time ago. Finally got it assembled, but have only flown it about 20 seconds. I also got the extra camera mount option, but have not yet attached it.
However the juice bottle bottom rig looks promising. Used furniture bumpers with double sided velcro, so can trim the position of camera within the housing. While tight, looks like a second one could be added adjacent to the one shown. Alternatively, a pair could be attached below. Images show a A495 and a SX260HS in the housing.
Time to learn to fly it. May be choice for days without wind when helium isn't available or where a line to the platform aloft is not an option as above tree canopy.