Good question. According to the docs your bundles need to be placed in one of the ApplicationPlugin folders on your local drive.
I tried a simple shortcut with the *.bundle extension naming format that pointed to another drive location, but this didn't work for me.
However in Windows 7 (I think for Vista too) you can create a junction link to another folder. I tried this for a bundle located on another drive on my machine and it worked. Maybe you could test to see if this works on your network.
To create a junction link:
1. Open the command prompt as an Administrator.
2. Use the Mklink command, for example:
mklink /j "C:\Users\<user name>\AppData\Roaming\Autodesk\ApplicationPlugins\MyApp.bundle" "E\MyAppBundles\MyApp.bundle"
For further details you can google it.
Here's a microsoft link: http://technet.microsoft.com/en-us/library/cc753194%28v=ws.10%29.aspx
The downside to this is that you would only be able to edit the files in your plugin when no-one has them loaded into AutoCAD (i.e. when assemby files are loaded into AutoCAD they are locked).
I haven't thought about how you would create the junction links on each machine, perhaps a command prompt batch file. There might be an easier way.
Would be curious to hear if this helps in some way.
Art