Lawdog,
Perhaps the best finish I've seen for attractively darkening a stainless gun is Birdsong's Black-T. We have had perhaps a hundred guns treated by them over the years... everything from AR-15s (in OD green) to multi-thousand dollar high-end 1911s. My H-S Precision VTD .308 is Black-T'd from the factory and the finish is very attractive and reasonably durable (as durable as a blued finish if not more so). I also have two custom 1911s with this finish.
You can get the action and barrel done (and scope mounts and rings) and the gun will be very attractive, protected from rust, and you won't need to use any lube in the action. It's not the cheapest finish, but it is the best of the 'coated' finishes, and we've tried every coated finish on the market.
If you're not familiar with Black-T, it is also used on all black-finish Benchmade knives (Birdsong does a couple thousand a month). I can't say enough good things about the company or the finish.