Command line sending mail with different "From"?

mail -a "From: Fake Person <fakey@gmail.com>"

Thank you! That worked. After testing this it brought up another question. When viewing the raw text of the e-mail message sent using this it will show it came from my original domain name (what is displayed by hostname -f):

Received: from mydomain.com ([72.14.xxx.xxx])

Is it possible for it to show the domain that I am actually sending from? I have two virtual hosts/domains served by Apache and the "Received: from" would always indicate the hostname -f even when I send an e-mail that is supposed to appear from the other domain. The From field displayed in the e-mail client does display correctly.

Not generally; your system has one hostname, which is used to identify itself whenever it needs to know its name. The best workaround might be to use a hostname under another, neutral domain (like a domain for your company/department, if other companies or departments are your "customers"). If worse comes to worse, the default lixxx-yyy.members.linode.com hostname works too.