Using the emf_webform module available here:

https://github.com/reload/emf_webform

I've written some code to allow users to fill out webforms containing various custom fields and send that data to the mail service. What I'd like to do next is allow users to change that information, and so the module would need to be able to query the mail service and ask for a subscriber's information.

As best as I can gather, EMF currently does not support this. I'd be willing to work towards support, but I cannot test it on any service other than Campaign Monitor, so I couldn't set up the MailChimp plugin to support it, for example.

Would you accept patches to do this, or should I just create a Campaign Monitor-specific custom module?