For the 50mm, the Voigtlander 58mm looks promising.
If the Voigt 58mm had been out in EF mount when I got my ZE 50mm Planar, I would probably have gone for the 58mm instead. They're both made in the same factory & the VL is almost half the price.
I already have a Canon 28mm f/1.8, and the focus throw is not terrible, but I'd be interested in something with around 180° rotation. Again, any recommendations?
I've got a Zeiss 35mm f/1.4 Distagon on an adapter (C/Y mount) that is my 2nd most used lens after my 24-105L. It's just brilliant, & I got it for 350 euros. Zeiss makes a 35 in ZE mount but it's pricey & "only" an f/2, and the 28mm f/2 is even more expensive (about the price of my 24-105L!).
16-9 has done a ton of adapted manual focus lens tests on Canon bodies and I find his comments to be very valuable. He's also got a few lenses with adapters for sale from time to time.
photozone also has a lot of reviews of adapted lenses on Canon bodies. One of my favorite features of his reviews is his extensive bokeh tests, which will probably be useful to you for video.
BTW I haven't verified this, but I would imagine that in Canon land the Macro and TS-E lenses have pretty long focus ring travel as well as they're more designed for MF than other EF lenses. Worth checking out. The EF-S 60mm macro is really good for the price (esp. as they're starting to be readily available used), and the new 100mm IS macro rocks. I've got to say that video looks really cool on a tilt-shift lens as well as long as the effect isn't overdone. There are a lot of used 24mm TS-E Ls on the used market now that the II version is out; I've seen several good examples in shops around town for 7-800 euros.
Hartblei Super Rotators are Super Cool (and the new versions are Super Expensive as they use Zeiss glass), but also pretty rare used & I think they've stopped making the non-Zeiss models...
Mirror telephoto lenseswill also have a super-long focus throw as only the new Sony one is AF. Evidently there's an old Vivitar model that has a fanclub. If you like doughnuts...
Some other crazy stuff to check out that's come on to the market recently:
The dirt-cheap but optically good
Samyang 85mm f/1.4. They're sold as "Boyer" at B&H. They've also got a 14mm f/2.8 on the way that's supposed to be pretty good. Note that though they use a phyiscal EF mount they have no electronics.
Noktor is a new company that seems to be adapting closed-circuit night surveillance lenses to camera mounts. We'll see how that works out...
A slight side-question: are there any decent fisheyes made for APS-C cameras? I'd imagine one designed for a full frame camera would lose a lot of what makes it a fisheye, ending up with an image that just looks warped.
Trust the Ukranians for fisheyes. The Pelengs & Zenitars are optically about as good as a fisheye needs to be, & you don't give a toss about focusing. I believe they come from the same glass factory that Hartblei used before they switched to Zeiss optics.
Lots of choices to make... Good luck & let us know how it works out.