Strictly IMHO..........
Since the Rossi is a clone of the Winchester 1892, the action has two locking lugs that have to move upwards to lock the bolt before firing. Whereas, the Winchester 1866 and 1873 uses a simple toggle action. Like a Luger pistol (upside down). So then, if I was looking for a fast lever action. I'd look at an Italian clone Winchester 1873, 1866 or a Marlin 1894.
Course, if you have the $, there is nothing wrong with spending the big bucks for an original. Hopefully never, but who knows, if/when the old parts may go.
If I was thinking about mounting a scope.....
The Marlin is easier to do. Because of the solid top and side eject. Not to mention that it's already tapped.
If I was looking for parts (it happens)......
The Win clones......well, Uberti parts and modified parts are very popular.
Marlin.....the factory is still making firearms.
Course, gunsmithing is available for your Rossi and most any firearm.
If you like to DIY, you might want to take a quick look at this web sight......
http://marauder.homestead.com/irons.html
Aloha, Mark
PS.....Marlin. Stay away from the new Rem-Marlins unless you can closely check them out in person.