There is a shotgun in the xbox and probably ps2 versions of RTCW due out sometime soonish, you can see shottie in the screens @
http://www.rtcw.jolt.co.uk/index.php?page=&action=show&id=2433 . No idea if it's travelled to ET aswell, dual pistols was in RTCW singleplayer but not multi, again dont know if these have passed onto ET but doubt it.
jrz there's a linux port of RTCW and since ID know full well the vast majority of servers run linux, I'd be VERY surprised if there isnt a Linux ET. As for Mac, there is a Mac RTCW made by Aspyr but this is retail... I guess it depends how easy it is to port.
Soupkin, given how cheap RTCW is now I don't think you'll be dissapointed anyway, the Singleplayer isnt fantastic but IS fun and rtcw mp, which is excellent, is still going strong.
Fair bit of info in this recent interview on CVG -
http://www.computerandvideogames.com/news/news_story.php(que)id=89752DG - www.rtcw.co.uk