I already have a means to rebuff in combat. A couple, actually - Smartbuff has a "rebuff in combat" mode, and for my shamans I have a specific key with a castsequence of shield followed by weapon imbue.

The sequence has a reset so that I can easily re-cast just my shield during a fight, which is all I need most of the time.

The only problem I want to solve is getting the timers on my main screen. Really.