My boss is the type of person who would rather pay more (loads more)
for a Cisco ASA because paid support can be found for it and there are
"lots of people who know how to support it". I need to counter these
arguments in order to implement m0n0wall.

1. Are there any companies in the USA supporting m0n0wall (paid support)?

2. What major (well known) companies or organizations (Universities,
etc) are using m0n0wall in production?