If you like the "Black Rifle" look, the S-16 and the Air Force Talon/Condors are about the only choices I know of. Unfortunately, the Talon's aren't repeaters, single shot only. Great little guns, though, I've had two.
Although I've never owned one, I've done some research on the S-16. I don't believe the power is adjustable, and it's closer to 1000 fps rather than only 600. By all accounts, the shroud is very effective, and being modular, you can decide how critical it is to your days shooting plans. It's heavy, around 8 lbs., and I've heard that there are issues with seals, they're prone to leakage. Also that the repeating mechanism requires a firm hand.
For the same money, you can get an Air Arms S410 ERB, 10 shot mag, integral shroud that's highly effective if my older S400 is any indication, and easily adjustable power, with a really good range on the adjustment. Of course, it's a more classic looking rifle, and you can't carry a spare filled tank. The older model 400 I just got is a .177, it does 27 fpe with Eun Jins, 23 with CHP's. 30 to 40 good shots per fill, might be higher. I have a discrepancy between the rifle gauge and my filler gauge. Check out the review I just did. This is a rifle you can literally take out of the box, fill, load, and shoot. All the glowing reviews of the 400/410's are true, they're just great rifles. Anyway, hope that helps, and keep us posted on what you decide on. Later.
Dave