Choice of Zimlet back-end development environment

[Steve Hillman <hillman@sfu.ca>]

For those of you doing Zimlet development, how have you chosen to develop the back-ends for those Zimlets that you want to interact with other systems, or manage their own databases of data?

It seems there are several options:
 1. Write JSPs that run on the Zimbra servers (i.e the "standard" Zimlet development model)
 2. Write in whatever existing Application Server Environment you have, leveraging existing code and database infrastructure, but making your Zimlets highly specialized
 3. Write small applets in something like PHP, run them wherever you want, and rely on the Zimlet proxy to allow your Zimlets to communicate with the back-end

Anything I'm missing? 

We're currently going down the path of #2. This shortens development time even for rich applications, but makes our Zimlets very difficult to share. I'm just curious, for those who've pretty much standardized on one approach, what approach that's been

-- 
Steve Hillman                                IT Architect
hillman@sfu.ca                               IT Infrastructure
778-782-3960                                 Simon Fraser University