I've heard a lot of jokes over the years about a playing a cello under the chin. Take a look! (and note the lack of endpin). Yes it IS a cello, albeit a small one. I'm thinking there's something historical going on here, but I'm a bit fuzzy on my cello history details - other than that violoncello actually means "little violone". Definitely a baroque bow, and the bridge is not your standard modern bridge.
Vivaldi Cello Concerto in D major RV.403 La Petite Bande
(inserting new video here - the last was had been removed from YouTube)
I suppose this might be the answer for a violist who would like to play the cello - I'm pretty sure he's using a violin/viola finger pattern.
Alternatively, if you're a cellist who would like to play violin, you could try this.
(Yes, this is Wells Cunningham playing BOTH parts, and by the magic of video and careful listening on those headphones...)