If the biggest cog out back on that Salsa is a 28, a short-cage RD would prolly work just fine. If an old-school NR RD can handle a 28, why not a modern slant?

I think many people might think a long cage is needed to get all the gears, but really, who would use the smallest cogs out back with the smallest ring in front? Or big/big? Cross-chaining extremes would likely not work with this setup, but gear-smart riders know the limitations inherent in their drivetrains.

Every time I see a photo of a bike on the Forum in the big/big combination I wince a little and think "those components are going to have a shorter life than normal..."

Of course, YMMV.

DD