I've been cropping my vertical photos using a 5:7 crop ratio, and it seems to be more pleasing. The 3:2 DSLR format when shooting vertically appears to be long tall. Its hard to have a pack the frame with the subject and interesting backdrop in such a long format.
I'm thinking about a mask for the viewfinder so that I'm framing to this 5:7 format. and one for a square format too. Gotta look into this a bit.
Update:
I did some digging around and it seems like it should be easy to take out the viewfinder. So then all it would take is some paper, maybe parchment paper affixed in some way to the screen on both left and right sides and that'd be that.
We'll see.