Soda bottles work perfectly fine. Soda is MUCH more highly carbed than beer, and if the soda lived through it, your beer will too. It's fine, and I've done it myself.
The only "problem" I see with 2L bottles is that when you pour a homebrew, you pour off of the sediment. That works great for 12 ounce bottles, when you pour into the glass. But with a 2L bottle, you'd have to pour in a pitcher and then drink the whole thing, or stir up the sediment each time you lift the bottle.
I'd bottle in 1L (or smaller) soda bottles, just for that reason.
In a soda bottle 1.5" of headspace is fine!