Since you mention the 3" 686 most people seem to be concentrating on the medium framed snubs.
You can (as said above) find a 3" 686, but they are only available used. If you want new and you want a 686 you need to go with a 2 1/2" barrel.
I love my S&W 65LS. Great gun! I hear (on this board) that they are discontinued. That is sad to hear, but for now you can probably find new ones at dealers if you want new (these aren't that easy to find used as people tend to hold on to them).
A 3" non-LS S&W 65 is a good one, but you can only get it used and 3" K-frames, while they sold a lot, don't show up often on the used market (owners tend to hold on to them, for good reason).
If you want new I think the only S&W medium frame 3" still available is the S&W 64 (the stainless M10).
A gun I'm eyeing right now in blue (though you can get them stainless) is a used Ruger Security Six with a 3" barrel (if it was a K-frame Smith I wouldn't be eyeing it, I would have definately bought it).
If you want to go used you might be able to find a used Taurus 82, 65 or 66 in a 3" barrel though they are rare. Unfortunately, Taurus doesn't currently make any 3" guns (I may buy a 4" or 6" Tracker in .357mag, .45LC or .45ACP and have it cut down to 3").
If you want a K-frame sized gun, but not necessarily a .38spl or .357mag look at the Taurus 441 and 431 (3" .44spls) or the Rossi 720 (fairly lightweight 3" .44spl), though these are only available used. New you can still find the 2" 450 (.45LC), 445 (2" .44spl) and 415 (2 1/2" .41mag).
If you want to consider 2" and 3" small framed snubs you have a ton of options. 2" Taurus revolvers in just about every configuration (9mm, .32mag, .38spl, .357mag; bobbed hammer, regular hammer, "hammerless", shrouded hammer; 5 shot or 7 shot in .38 or .357, 6 shot in .32mag, 5 shot in 9mm; aluminium, titanium, or steel). There are also a ton of S&Ws.