UI with single tab containing all messages?

I’m looking to modify the Spark client (or find a different client) to display all messages in one single tab.

A separate contact list and other containers are fine, but I really want all messages to show in one tab/window. It would not be a conference room since the IQs themselves are 1 to 1. (Click on the user’s name to send them a message, but all messages show in the single tab.)

Does anyone have advice on whether this is better accomplished in a different client, or is it a viable option to edit Spark (via plugins, or the UI itself)?

Regards,

Tom