Burnham, are you sure you need 50ccs for a small clearing up saw, like the 260? Seems like the low 40ccs is what you'd be wanting....a high reving saw with some grunt. Don't know what exactly is out there currently that might fit the bill, though. Guess that you want a Stihl....
My 242xp is all I need for limbing and small bucking. It's had it's lid popped, however. Fast working saw, but no longer made. You don't want to expand your considerations to other brands? Husky might be a better choice for a smaller saw, or?
Raising the compression on a small saw can be very helpful. More arm to pull it over is the downside, if on and offing it a lot.
A friend brought me his MS200 and asked if I could do anything to get more power from it. It was running rich, and adjusting the carb helped a bit, but I wanted to lean it out to oblivion, the thing seems rather gutless.
What sized bar are you thinking to cover your needs?