It's been done. This APUG thread covers the topic in some length. In the 1980s (plus and minus a bit), several commercial outfits sold "short ends" of motion picture film for still photographic use. I used some of that film at the time. My overall impression today is that it wasn't optimal for still use, and I wouldn't recommend it for that use today unless you want to experiment with materials that are a bit different for specific artistic purposes.
There were a couple of companies that used to package motion picture film, and you could mail it back for the processing. IDK if they are still in business, I think Seattle film works was one. Motion picture film uses a different development than normal color neg. In general, the average still shooter would see little or no benefit in shooting motion picture film over regular color neg. OTO, if you have a good amount of experience with it, it is exceedingly flexible.
To the best of my knowledge, none of the photofinishers that used to respool motion picture film for still use still do so, although the last I heard, at least one (Dale Labs) would still process the film. To use motion picture films in a still camera today, you'd need to buy short ends (or a whole roll) and spool them yourself.
I've developed some rather dated kodak 5245 last week in tetenal c41 kit. Works fine, colors are quite normal, pleasantly neutral, great latitude. No special artistic effects. But mind that my typical color material is a cross processed slide and I've shot just a few rolls of normal color neg in whole life.
It works in c41, but remjet is the problem. You can't run it through a minilab, you have to develop it yourself and scrape the remjet manually. I think hardly worth trouble in most cases.
The question is how much do you value your time. If you process it yourself. It will take more time to do than doing C-41 just because of the remjet. Now the contrast will be off since the print materials for MP film is higher contrast than paper. I've only used the ECN-2 chemicals with it so I don't know if the contrast will be diffrent crossed in C-41. I do know that the lifespan of the dyes will be shorter if done in C-41. ECN-2 uses CD-3 wereas C-41 uses CD-4. I would imagine that it would have the same stability problems that cross processed slides would have.
One possible fix for the contrast problem that comes to mind is to fix the film then bleach. You would then expose the film to a strong light source while on the reels then redevelope bleach then fix. It would increase the color saturation as well as the contrast. I haven't really tried it yet but given the properties of color film it should work. BTW you would need to use a rehalogenating bleach.
A and I bought RGB color labs machinery and set it up last year. The prices are much higher than RBG's were but the set photographer demand for it isn't there anymore. We're lucky to have anyone that'll do it anywhere! They sell rolls of kodak and fuji stocks too. The latitude of the vision stocks is very wide and those films printed on paper have a nice look that's just different.
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