I got bit by the nano/piko/femto quad bug and had to make one. I liked the look of @microdure's frame, but it was bigger than I wanted. I had already started working up a very minimal frame design and printed it as 80/90/100 mm....but didn't notice the motor shaft on the BR1103 motors extended through the base. Since I had to redraw my motor mounts anyway I decided to try and design a frame more like microdure's only in the 80-100mm range since a bit of motor protection would be nice to have knowing how often I crash things.
Frame is an easy print, that takes just under an hour on my printer at 0.25mm layer height. I also included some small m3 spacers that make it possible to use the TX-02 camera mount I included as a source.
You will need to have o-rings under your FC for clearance - or you could mount it upside down or remove the DSM port. I used O-rings. The FC mounting holes are slightly undersized from M3 since I used an M3 tap to thread them then mounted the FC with nylon screws. You could drill them out and use nuts on the bottom if you don't have a tap.
With a 450mah 2s battery, LemonRX DSM sat RX, and TX-02 FPV cam/VTX this comes in right at 80g ready to fly when printed in PLA with 15% infill
So far this has held up better than I anticipated printed in PLA with 3 perimeters and 15% infill. I've crashed it full throttle into my house and sidewalk several times and the frame hasn't broken yet. I may try printing it in ABS since it should be lighter and a bit tougher...but PLA has worked great so far in a few days of crash testing.
As noted in the description you'll probably want to use an M3 tap to thread the mounting posts.
I also drilled out the motor mounting holes - they're sized properly in the STL but 1st layer squish tends to block them up a bit. A #52 or #53 drill bit works great. The motor shafts cleared the center holes fine but I cleaned them up with a #57 drill just to be safe.
I used a LemonRX DSM satellite RX which I removed the connector from so it would fit easier inside the frame under the FC.