Any decent SMS gateway should let you send messages from who the hell you want. Add far as analogies go, it works pretty much the range as email, and would take the same fundamental redesign to fix.
You can do this from any SMS gateway, as there is no real verification. However most gateways do not allow their users to spoof the sender because predictably the carriers do not like it.
We have this feature in 8centsms.com but we verify ownership of mobile numbers. We've had problems with spammers sending fraudulent "from" headers like "BTUK" (ie. british telecom) so we recently put in some checks to ensure we have to manually verify each account once they spend up to a certain amount. I think that if you're blindly allowing people to spoof the sender id you're just asking for trouble ... Also this seems to be a pretty expensive prank ;)
You can use this trick to listen to anyone's voicemail (by identifying the calling number as the recipient's number) if they do not have a password. Anyone. Talk about security hole.
Wikipedia has more information for the interested[1].
[1] http://en.wikipedia.org/wiki/SMS_spoofing