http://basedremote.com/ is an excel list of companies offering remote positions, you can filter the list, albeit not by size.
At first glance the following match your criteria (don't know exactly what your criteria are for BigCorp)
https://www.salesforce.com/
https://www.palantir.net/
http://www.oreilly.com/
https://www.digitalocean.com/
http://www.linuxfoundation.org/