Any reputable company or corporation would have their own domain. The claim that they are a world wide corporation and using gmail screams SCAM, looking for any sucker out there!
Yahoo, Gmail, Hotmail, AOL, ATT, MSN, and many other free online email providers are notorious for the origins of scams. Especially the first three. They are too easy to set up an email account that is untraceable to whomever registered for it. They can do their hit and run scams and not worry whether or not the account gets deleted. They'll just sign up for another from some cyber cafe or mobile hot spot under a different name from a different ISP and do it all again.
If you have friends with an email account with any of them and your friends keep your email address in a contacts or address book with that account, chances are their account has probably been hacked to get all their email contacts. If you have an email account with one of those free online email providers, chances are that your email account has probably been hacked to get at all your contacts/address book.
If you use Facebook or any social network and reveal you email address, you can expect many more scam emails / spam
Its on my model mayhem account as well and that is how this person found me, the day it become viewable by the public. 

