high end tour companies regularly come up in the 3 luxury travel magzines i have linked in the sticky in the luxury hotels forum.

you might be especially interested in elite traveler's "14 days" feature, which they have every issue. (for the contacts/sources)

the latest issue - 2 weeks golfing ireland and scotland >
http://www.elite-travelerdigital.com...6/?pg=186&pm=2

article featuring 10 companies in current departures >
(whole issue is devoted to experiential travel/tours/etc)
http://www.departures.com/articles/out-there-outfitters
(john smith / 371909)

forbes is also a reasonable source, though much less frequent >
http://www.forbes.com/travel/2008/06...618travel.html
http://www.forbes.com/2008/04/25/tra...425travel.html
http://www.forbes.com/business/fyi/2008/0421/087.html
http://www.forbes.com/2007/10/08/adv...009travel.html
http://www.forbes.com/travel/2007/08...802travel.html
http://www.forbestraveler.com/advent...urs-story.html
http://www.forbes.com/home/2007/01/0...nesstours.html
http://www.forbestraveler.com/advent...urs-story.html
http://www.forbes.com/travel/2004/05..._0506feat.html

http://www.forbestraveler.com/luxury...ies-story.html