Thanks for the feedback everybody!
At this moment in time, the FXI Gravatars plugin does exactly what I need it to do for the FX Instructor forums, which run VB 3.8.5, and while I'd love to add the features suggested in this thread, I simply don't have the time to dedicate to it.
I've enabled code-reuse on this mod, so if anyone wants to try their hand at one-upping me, you're welcome to it. I might pop back over and work on it some more if my schedule changes - but at this point it's unlikely.
I hope you all continue finding this mod extra-helpful and use its code to further benefit the VB community.