I work for Canonical (www.canonical.com)
We have some offices and legal presence in some countries that require it, but most of the engineers are work-from-home only. My team is completely work-from-home, including manager, product manager, and QA engineers. We're 12 in 7 different countries and 3 continents (used to be 4 :) )
Only designers and some sales people have a hard requirement to be in the office, AFAIK.
EDIT: for the sake of my personal pride I updated the numbers of countries my team is distributed to. it was WRONG. I hate wrong! :)