Hey,
Thanks for reaching out. I'd love to hear form some others on the forums too. What would the interest level in a Linux SDK be? What distros do you all use?
Actually, you can get everything working under linux. Just requires some tinkering and installing wine to run the simulator under and having the right version of Java (all the compiler stuff is java based, so any platform that runs Java can compile things -- only the simulator is platform specific).
I don't use eclipse (honestly, hate the environment), but have a few scripts that do my building, signing, etc and launch the simulator. If you're developing under linux, this isn't hard to get working (again, a few manual steps, like starting the simulator vs the eclipse plugin being able to). I've developed three working apps so far.
Bigger issue is that the simulator is not really a very good test for various watches -- lots of minor diffs between it and the real thing. But that isn't a linux thing ;-)
There is a good "bootstrap" on what you need to do to get this working under linux. It'll get you going in the right direction, though I do recall one or two obvious small changes that had to be made before it all worked.
http://blog.aaronboman.com/programming/connectiq/2014/11/13/the-garmin-connect-iq-sdk-on-ubuntu-linux/
Gerry