I wouldn't trust a pair of LDs on it personally, but I believe in trending toward engineering for overkill when it comes to safety. If you're going to do that, atleast make sure you use the 3/8ths connector and not the 1/4.
......... Hard to beat that rig for size and (I imagine) cost. Is it stable?
mine is, I use the rapid adaptor purely for orientation purposes. When it's horizontal and screwed on tight, the shockmount doesn't move (thread tight on the adaptor) and the RA doesn't move since gravity is working against the stud (and it's screwed on tight with a raised lip between it and the exit).
I could even hang stuff up side down courtesy of that raised lip which would prevent the mics and mount from falling off in the unlikely event that the rapid adaptor screw came a little loose.
Just make sure to look up what the posted failure weights are for the nano. It's something like 7lbs which isn't a ton, but it's more than enough for standard SD mics and active/remotes.
Page what kind of Stud is screwed into your Nano?
check tim's thread on clamping, it's near the end of that, macdaddy recommended the stud as I was originally using a slightly longer one. I think it's $4 or so.