My work flow
I have /usr/local/emhttp/plugins shared over the network.
I do all development work on a Windows box with the files opened in Network++
When I want to either publish or test out the plugin on another system, I just issue two commands in my putty session that copies the files back on to the Windows box (which hosts the local GitHub repository), and builds the .txz On the other servers, I simply installpkg the .txz from the Windows box (the repos are shared over the network)
When I publish, I just change the version of the .plg file and update the md5 listed in the file and push to GitHub.
Works perfect and painless for me. And has the upshot that I can directly program on any of the servers and easily build the txz to test the changes on the other ones.