I have a 2002 Trek X0-1. As some of the parts have worn out I've replaced them with touring-like components: bar-end shifters, beefier wheels, larger cassette, etc. In terms of components it's set-up more like a touring bike than an XC.

I haven't done any expedition touring, but I've been very happy with it for a couple week-long light tours I've done. The geometry isn't the best of loaded touring, but as someone else mention I'm sure it would work well with a trailer: That's the great thing about trailers - they can turn almost any bike into a tourer (though they can be cumbersome if you're weaving through traffic).