I'm seeing no reason the Varia can't be mounted directly behind the seat - attached to the seat rails, instead of the seat post. On my bike the Varia mounted to the seat post takes up all the real estate behind my bike, anything else I try to put back there blocks the radar.
Mounting high behind the seat would let me stash a spare tube in a saddle bag UNDER the Varia, use the seat post for a Fly6 or alternate blinkie, or put a low profile container on top of a rear rack.
All the mounts that I can find that enable this are for Go-Pros, so the solution is to buy a GoPro seat rail mount, then buy a Go Pro to Garmin Varia adaptor.
That's $55+ I'll spend to mount the Varia that Garmin's missing out on. I can't be the only one with this issue. Would they consider manufacturing a seat rail mount for the Varia Radar?