My Amiga Workbench is running at 1280x720 normally, since FS-UAE is letting me take advantage of UAEGFX for some really nice high res screenmodes. I did a little cherry picking from some ClassicWB setups to get Picasso96 and the screenmodes needed, but I'm pretty pleased with the results!
I do want to post a newer screengrab of my Workbench, but the image limit here is rather restricting (and the smallest I can make the grab is 393KB if I save it as JPEG!)