Some of the people to talk with regarding your questions are:
Buzz Burrell - Manager, La Sportiva GoLite Running Team
Nancy Hobbs - Chair, USATF MUT Council
Matt Carpenter - legendary mountain runner and cofounder of the Barr Trail Mountain Race, which he won again yesterday
Dave Dunham - race director, Northfield Mountain Run and others on the USATF NE cicuit.
(I won't post their contact info, but their email addresses are easily found). The Central Mass Striders also have a good men's team with some mountain runners on it (www.cmsrun.net), including Paul Low.
These people are very approachable and informative. The mountain running community is a friendly, interesting and close knit one. The is not much money in it and I don't believe the sponsorship levels extend beyond travel and gear. However, the racing is very competitive and rewarding. In Europe, the racing are quite high profile and there is quite a lot of money involved.
And for you track stars out there, please don't assume you will jump into mountain running for some quick money. To give you an idea of what you will currently be up against:
Matt Carpenter - VO2max of 92 recorded at the OTC in Colorado Springs. Ran a 2:52 marathon at the Fila Everest Sky Marathon at 14,435 ft of elevation!
Simon Gutierrez - 3 time World XC member of US team, 3 time Mt. Washington winner. PRs of 14:20, 29:15, 1:03 & 2:18.
A few track/XC from Colorado universities have done very well in the mountain races the past two years. Tim Parr and Matt Levassiur, who train and live at high altitude have excelled on the mountain. Levi Brathall from Colorado Springs ran well at BMTR yesterday as well. Clint Wells did surprise at the Vail qualification race in June in the snow and mud. But he is excellent at altitude and obviously a tough runner. Other athletes, especially snow shoe experts and triathletes, tend to do well in the tougher, steeper races. For example, Josiah Middaugh from Vail has done well, following his US Snowshoe championship and Xterra overall win.
However, there has been some success from the East Coast as well, maybe due to the great circuit of events they have there. Ryan Pauling from NY just made the US team by winning the Wisconsin qualification race yesterday (crawling across the finish line apparently). Eric Blake and Paul are two other very successful mountain runners from the east coast.