Loose, impressionistic western landscapes with a big bold flair are certaintly "a type". I'm not universally wowed by the genre, but this guy is a fantastic practitioner: http://www.christensenstudio.com/ His field sketches in particular are amazing... I think I like them better than many of the large studio paintings.
Browsing through the materials list for his seminars, I found a couple of noteworthy things. First, his palette is extremely limited -- white, 3 primaries, and 4 grays. Second, he was able to have the manufacturer pre-mix those grays for him... that's very cool.
The decision to use a limited or extended palette is interesting to me, and I'll write another post about it later. In short, though, with an extended palette (say, 30 colors or more), you have the opportunity to approach real-life colors with some fidelity -- nature is nothing if not a jumble of information. With a limited palette, you lose some of that verisimilitude, but you gain ease of use, control, and the ability to deliver an extremely powerful color harmony, almost automatically. I'd go so far as to say that his color harmony is a large part of what gives his paintings such elemental strength.
Another thing just occurred to me. Atmospheric perspective seems to force hue, value, and chroma into narrower bands. Objects in Scott's paintings are often far away -- that mountain range 10 miles off. Limited palettes can be used to great effect in portraying smaller families of hue/value/chroma. I wonder if he'd choose so few colors if he primarily focused on closer objects.
I have in the past used very limited palettes for still lifes, even, mostly for darker, Dutch-inspired stills. Lately, however, I've been interested in making more vividly colored still lifes, and therefore I use a much broader range of paints... upwards of 40. Both can be very convincing... more color is where I'm at now, though.