Ken Roberts wrote:

I've heard some scary stories of people who did one of those big climbs in
the U.S. and did try to descend on their rollerskis, mentions of surprises
and scar tissue.

I guess so! :-)

I think actually the west
side has similar steepness in its steep sections, but not as sustained --
and for it has more variety and interest as a climb, and much more fun as a
descent.

you can check the two profiles he
from Bormio:
http://www.salite.ch/stelvio.htm
from Prato allo Stelvio:
http://www.salite.ch/stelvio1.htm

as you can see, the latter is a bit tougher, but nothing impossible (at
least by bike, that's the only way I did them...I never tought about
rollerskiing up there 'cause I would not know how to come down!).

Since this is a nordic skiing NG, there is a funny, recent piece of news
about Stelvio: one of the italian national team x-country skiers (Tomas
Moriggl) was lost up there last weekend: he went for a running training
in the late afternoon, then he got lost somewhere and he spent the whole
night up at 2500 meters in shorts and tshirt...he said he kept on
running the whole night to avoid getting too cold...then they found him
the following morning :-)

I did not enjoy descending those 48 switchbacks on the east side -- next
time if I climb up the east side again I would descend Umbrail (including
its 3km of gravel as noted by beorn) and make a loop back to Prad through
the Mustair valley in Switzerland.

yeah, that's very nice, but also descenting the 48 swithcbacks is nice :-)
last time I did it it was raining and hailing, but it was cool :-.)

Switchbacks -- When I have bicycled or skated up these big alpine climbs, my
experience has been that "switchbacks are my friend" -- the steepest
sections of these climbs are usually in between the switchback sections. I
suspect that once the engineers decide to put in switchbacks for some
section, they show off their design skill by limiting the steepness. So when
I made it up out of the trees on the east side climb and saw all those
remaining 22 switchbacks above me, instead of being intimidated, my reaction
was, "This one's in the bag".

I understand what you mean :-)

--
beorn
"You've got to learn to crawl
before you learn to walk"
Aerosmith (Amazing)