I've experimented with this before. The way I got it to work was building the plugin into a source distribution. This will make an LLB file. You can then drop the LLB into a plugins directory in the application folder. I made it so that each LLB would have to have a VI inside it with the same name as the LLB. This would be the plugin name, which I would use to populate a plugins menu item. When a plugin was selected, open a reference to \plugins\plugin name.llb\plugin name.vi.
I don't know if this is the "best" way to do it, but it worked for me. I'd like to hear of a better way, because I might implement this in my current project.
Thanks this essentially what I came up with. I used the save with options to move all files to the llb, and only had sligth modifications to adjust for the extra path in the relative paths. the save with options is very nice, even protected my llb and took out the code so now all I have to do is send a single llb. I was struggling to remember this oprion this morning.