Thanks for your offer to contribute. A private message system is on our road map but work has not begun on it so if you would like to send in your code we can evaluate whether to use it or parts of it. Before sending any code though, you would need to send a signed contributor agreement, you can find a link to the agreement on this page:
If you can provide the agreement then you can zip up your code along with any notes or instructions. From what you've said probably we would not use the code as is but would refactor it and use any parts that we can.
As far as the silverlight UI,we might make that optional to use but for sure we need a way to implement private messages without requiring the silvelright plugin, so we will have to implement an alternate UI with html but maybe can still make the silverlight one also available.
The ability to reply from email is nice but obviously it is a separate thing from mojoPortal that must receive the email but if there are steps that can be instructed how to make it work then some people may be able to use that.
So, if possible please send the agreement and then send the code and we will review it. Ideally the agreement should be an original signed copy sent by mail, the code can be zipped and sent to joe dot audette at g mail dot com but I will not look at it until I receive the agreement.