What are the GnuCash issues with cross-platform? We used to use it via dropbox on mac, linux and windows and never hit any obvious problems.
The UI however...
So it'll see a comma when I open the file on windows and just report an error.
Right now I'm considering running it in on my server and then connecting to it somehow from all the different platforms.
See the part about adding an environment file on Windows. On Linux, I set my LANG to en_US.UTF-8 but all the LC_* variables (apart from LC_ALL) to en_CA.UTF-8 and that gets me the right UI/formats mix in GnuCash (and also Chromium, which tries to speak British to me otherwise), and hopefully that works on Windows too.