No real new 3D /sprites are required, I think... Just maybe do a frame or two of the vaulting pose?
High AP cost (and vulnerability, if the engine calculates that sort of thing), but give the ability to climb out a window.
I searched for this and nothing came up so...
Crawling through windows:
basically my ideal would be to make windows kinda like barriers, where you can jump over them. I think the only extra thing needed would be a code check on whether or not the window has been destroyed. should be a pretty easy to add feature and also makes sense. why do I have to walk 20 grids to the door when I can just jump through this broken window* I guess the best way to balance it out would be to make it require a fairly decent amount of action points.
how does anyone else feel about this?