Blackberry services down in Europe, Middle East and Africa
bbc.co.uk
bbc.co.uk
It's nowhere near as big as the corporate market but it's there.
Any wildly popular (wildly is debatable, nonetheless they have many customers) service can put itself in to this situation if it does not have failover cases.
You are right in that not properly having some type of failover and thus funneling all traffic to a single region or datacenter hurts.
I would have thought that a Corp as big as RIM is that they'd be able to hire some seriously good talent which address this issue. Especially since I believe one of the big points they use to sell to business is the 'Enterprise stability' line.