The old OM series are nice and compact SLRs. Most of the older Nikon SLRs are higher magnification finders than the more modern cameras, at least in the more compact bodies. I think the F4 recommendation is good, though I would suggest you actually pick one up and handle it first. The usual F4 you will find on the used market has a vertical grip, and is quite heavy. Even with the normal grip, it still packs lots of weight, and has a fairly large grip for your right hand.

An F3 is more compact, and has finders that can be changed without much trouble. There is a somewhat less common sports finder (F4 and F5 also had these), which would be really easy to use. The flash issue can be worked around with a few Nikon items that convert the old shoe style.

Since you already have Canon, you might want to look into an older Canon F1. The lenses from your EOS won't work, but these are nice system cameras, similar to the Nikon F3.

Another nice system camera, with nice lenses, is the Pentax LX. This is still relatively compact, and very well made. I still know two professionals who use these for their work, one of whom is in his fifties and wears glasses.

It seems more like getting away from command dials, and back to regular knobs and controls. Definitely pick up and try out any camera, if you can find a nice example used. You might also want to look into getting a rangefinder camera, though the spending levels are often higher than many older SLRs. A rangefinder can often be a little easier to use for eyeglass wearers, though there is a slight learning curve to getting use to the focusing and framing methods.