where can I get cross sections/profiles of the Himalayas/Everest, the
Marianas Trench, deserts, ocean floor, other key land features of the
earth.  Cross sectional profiles, 2D image

Think this may give you what you are looking for
http://pubs.usgs.gov/publications/text/dynamic.html

But if you are looking for detail info you can find it here:
http://infotrek.er.usgs.gov/pubs/

like any search engine type in what you are looking for, for instance:
'Cross secction mantle' (without the quotation marks) that will give
you "Geologic and crustal cross section of the United States along the
37th parallel a contribution to the Upper Mantle project" which you
can buy for 7 bucks