Is it possible to do this? I'm sure it is, since you can send an email to someone from any address. The new MMS apps in the App Store send MMS through email and the receiver gets the pics as an MMS. The only problem is that the person receiving the pic gets it from a strange number or an email address instead of your number. If someone could somehow come up with an app that sends pictures through MMS like Multimedia Messaging, iSendMMS, etc. in the App Store but show my number instead? I assume this would allow the person to reply directly to your message instead of having to close the message and find you in their contacts or another message you sent them and press reply. Then it would look like you're sending a normal MMS to the person that's receiving it.

So yes, if someone can find a way to do this and make an MMS app like MMS in the App Store, we're 1/2 way there to having [basically] true MMS on the iPhone.