Hey Armaan, thanks for the message! Things are still going great! I've been mostly reworking the script parser and some other behind the scenes sort of stuff for v0.5, so unfortunately there hasn't been anything visually interesting to share recently.
I think what you're wanting to do will definitely be possible later on. The details aren't worked out yet, but I have plans for some "custom UI" functionality in the UI Editor for creating custom windows and widgets to complement the predefined ones. It will be a bit involved and come sometime after the v0.5 release, but it for sure is on the roadmap. And no worries about using RPG Maker, haha. RPG in a Box is meant to be its own thing anyway, so they each can serve their own purpose. :)