3D Printed frame mount
We will be offering a universal frame mount for sale within the next couple months. But in the meantime, here is the prototype 3D model that you can use to 3D print your own bracket. PLA material is plenty strong enough, just use near 100% infill. Use a piece of soft rubber between the bracket and frame. An old inner tube is perfect. Clamps to the frame with ordinary cable ties. Use a pliers or cable tie tool to get it good and tight.
A water bottle mount existed for the XShifter product. But the problem with this is that the cable becomes so long, it almost defeats the purpose of having wireless. Very few people actually used it. We recommend mounting the Quantum as close as possible to the derailleur, and preferably direct mount.
Xshifter was 1X and using a water bottle mount for RD might not be a good idea. I'm thinking along the line of using the Quantum Shifter for a Shimano or other FD, besides NSX FD. Unfortunately there don't seems to be a easy way to use a normal Road Bike FD with Quantum shifter. The only option that might work in theory is a side swing FD but those are MTB only.
You are correct. There is no good way to use Quantum or the old XShifter with a road front derailleur. Some people did it, but it was messy. You could probably find a top pull derailleur and use a cable, but it won't be pretty on a road bike.
This is why we are making our own FD. Its currently going through a redesign. The original design used the Quantum as the "engine" to power it. This wasn't a great result. The final design uses its own dedicated mechanism. It will be much more compact and robust. Its going to be a few months away, but we think its worth the wait.