There was someone on dpreview who used a Nikon D810 with their 14-24mm lens on a S1000. Found it: D810 & 14-24 over Iceland (Drone Photography): Nikon FX SLR (DF, D1-D5, D600-D800) Talk Forum: Digital Photography Review
It does sound like he hobbled it together verses another who used a Canon Mark something and found the gimbal easier to use as well as the camera plugins with the Canon. The link above shows it in his thread "Technical Information."
I did find some other cheaper drone which holds a D800 here: Infinity-6 RTF: V2, Dual Operator, 3-Axis Gimbal, FPV, Retractable Skids, 16,000mah 6S Batt, Charger Looks like a bit of DIY too.
Don't know how the X5S will perform either, but at least there are some good lenses out there for it.
Casey thanks very much for links
I have the same photo higher gimbal on my another octocopter ,but I should replace existing servos with gimbal motors ( prox conversion price $400 us).
I am looking for third party gimbal that would fit and work s1000+ a3 and light bridge 2 setup.
I am also wondering if someone knows if zenmuse for Canon could be converted to nikon d800 ( if it is just mater to fit the camera to the gimbal , it might be no problem for me to fit it on ,but I am wondering if the light bridge would work with nikon) .