I have a Shimano RSX 46-36-26 crankset, with a 110 BCD. I would like to change the 46T big ring to a 50T big ring. I can't find a 110 BCD 50T Shimano chainring. Will one by another manufactuer (FSA, Sugino, Stronglight) work?

Yes.

It would be nice if the CR had the ramps and pins, but it doesn't matter too much who made the CR, if the BCD is correct. Most CR will have the ramps and pins for the mid and large CR these days. The smallest CR doesn't need them.
Steve

The TA Specialties "Alize" chainrings are ramped and pinned for a triple. They make a 110 BCD 50t. My wife has a 49t Alize big ring.

Al

DieselDan,

Large (over 46T) chainrings are less common in 110mm BCD than 130mm, though as others have mentioned, not impossible to find either.

What I've found, however, is stainless-steel rings of this nature are next to impossible to find.

I don't know if material is important to you but I want rings that last a long time so I went to 130mm BCD.

My 2-cents.

I left out that I have found 50T chainrings with a 110 BCD made by Campagnolo, FSA, Stronglight, and Sugino. Heck, I even found a 55T.

Watch the Campy ring. One, or more, of their top line compact cranks use a nominal 110 mm BCD but off-set one bolt so they aren't compatible with everyone else's 110 BCD cranks.

With the advent of the "compact double" crank, lots of manufacturers make larger chainrings for 110mm BCD. I just bought an FSA 50t for $15 on eBay.
Pins and ramps and differential tooth profile make for nicer shifting, but you don't really need them.

Looks like you can get whatever price range you want, and choose silver or black.
Steve