Well, I know two left handed people who play guitar.

One is my brother - he's a year younger than me, and learned on my guitar. He plays 'left-handed' but with a right handed guitar upside down, hence all the strings are backwards. But he learned this way, so no problems for him.

The other is the rhythm player in my band. He's left handed, but plays like a rightie. Says it's easier to do the fretting with his dominant hand.

As a right handed player, playing 'right handed'... maybe I'd be a better lead player if I used my right hand to fret? After playing for 21 years it'd be tricky.... ;)