With respect to packaging, you may wish to check how it is done for comparable modules:
About the interface... what do you actually intend to expose to the perl developer? (I'm just curious, you write what you please ;)
I don't really understand the rational behind these "do the client-side as some transparent aspect of the server-side" frameworks (eg: ASP.Net, GWT), but I'll just assume it's because I lack the "enterprisey" gene.
I quite like jQuery's approach... Prototype done in a cleaner, more declarative fashion (although I hear the Prototype folks are catching up).
-David