I don't think you really get anything by putting a Canon VI-L alongside the 7SZ; they're pretty similar cameras following a lot of the same design ideas. The only real change is the classic Canon combined RF/VF that allows you to change magnification between 0.65x, 1x, and 1.55x views on the VI-L.
In my eyes, if you're looking for a second body, you want to find something that's going to bring something else to the table.
Sticking with Canon, you could go for any of the -T models for the built-in trigger winder, or one of the earlier bottom loaders for a smaller, more solid-feeling camera (I've never liked the SLR-style flappy backs of the later models).
The obvious choice would be to consider a screwmount Leica; they're relatively cheap by Leica standards (you can get one in good shape for not much more than the average Canon), and they're noticeably smaller than later Canons and feel nicer in the hand than
any Canon (I'll take rounded ends over the angular ends of a Canon, thanks). A IIIc or IIIf is the most common option (the RF and VF eyepiece being closer together on models from the IIIb onwards makes for faster use, and the IIIc and IIIf are usually easier to find than the IIIb), but there's a lot to be said about the feel of an early Leica III or IIIa. Controversially, I'd skip the Leica II as a user - the RF on those is only 1x, so they're harder to focus than the 1.5x RF of the various III models.
You could also go for a Leica Ic or If as a dedicated super-wide body that would match the Snapshot Skopar - that's (almost) the smallest possible platform for one. The Standard, especially in black paint, is a beautiful thing and a fraction smaller, but it doesn't have strap lugs, which is a deal-breaker for me.

(I'm not sure how well this translates in a photo, but the Leica Ic makes the Canon 7 feel
massive.)
There's also the Bessa options: most of them have racked up in price now, but they're still worth considering. The T is interesting - no VF, only a RF, so you need accessory viewfinders - and the L doesn't have the RF or VF. The Bessa R is basically a more modern equivalent to the late Canons. All of them have built-in light meters that will be a lot more reliable than the ones in the Canon 7 or 7sZ.
Finally, there's the "off brand" choices from Nicca and Leotax. Personally, I love a late Leotax - they made genuine improvements to the Leica III design without getting weird for the sake of being weird like Canon did. You can usually find them for a decent price, too. Here's a page explaining all the models, but I don't think you can really go wrong with any of them:
Leotax Rangefinder Cameras