The CV APO-Lanthar 180/4 is probably the best smallish tele I've shot with. It's excellent stopped down. Hard to find and fairly expensive, but a fine optic at any distance.
Everything else I can think of isn't going to be a huge seize and weight advantage. The Vario-Elmar-R 80-200/4, for example, is a very good landscape lens, but it's not exactly small. I own the FD 80-200/4L, which would save you some weight, at least (and it's not typically an expensive lens), but I have no idea how it performs at infinity. Looking over the shots I've taken with it, I don't think I've focused it beyond five meters. I'll check it out and let you know.
It would help if you specified focal length and price constraints. The CV180 everyone raves about is small and spectacular, but not easy to find (especially if you don't like buying sight unseen on ebay) and rather spendy. Stopped down the Oly 200s are good (fair bit of CA wide open). Bigger than those but smaller than your zoom I like the Nikkor 180/2.8 ED. Fastish, very good wide open, even better stopped down, cheap (they made shedloads of the thing) -- can't beat that.
One more vote for the Oly 200 f4. Small and light, perfect on the Sony a7 body. For a little more reach, the Oly 300 f4.5 is also nice, and has a tripod ring to boot. I have both and vouch from experience.
I still haven's found anything better than my Leica-R 135mm 2.8 V1. Apparently the V2 is better wide open but less good stopped down. Various other legacy glass in this FL ( Canon FD and Olympus)suffers from excessive CA ( not a massive problem) and purple / green fringes to bokeh (unfixable). Sometimes I think I'm better off with the weight and bulk of my 70-200 2.8L with the IS and fully corrected modern optics. Maybe the 70-200F4 +1.4 extender?
It looks like an earlier version of this lens. It's difficult to tell for sure, but the lens in the KEH photo appears to have bright steel ring reflections at the ends of the focus ring and lens barrel (it might just be light from the strobes). Mine is a relatively new MC version that looks like this,
In terms of sharpness I would rank these in order of sharpest to least sharp:
180/3.4 APO Telyt Leica - any vintage/serial number
180/4 APO CV
180/2.8 Canon AF
200/4 Nikkor
The Leica is supremely sharp and absolutely no CA, but the heaviest of the bunch. The APO CV is just a hair behind, while the others are definitely a notch down in sharpness, CA, etc.
Not sure if you're looking for a zoom, but in addition to many of the lens recommendations above I'd look at the Leica M 135mm Tele Elmar. Great image quality in a small package.
