Not just moments ago, I posted an article about Lensbaby's new Sweet 35 lens for their Optic Swap system. If you're looking for a cheaper way to get into some
make-shift tilt-shift photography, here's that popular DIY Tilt Shift Photography Tutorial from Make Magazine. On Flickr it's also coined as the 'plunger cam'. Nothing like real $2000 dollar TS lenses, but you'd be surprised at some of the images that have been snapped using this technique. If you don't want to use a cheap plunger, more professional versions of this has been made with Volkswagen CV Joint Axle Boots.
Obviously you'll lose all camera to lens communication, so this DIY is best used with Manual focus and manual aperture lenses. Since it's just a floating lens on a rubber bellows it's not so important which camera mount you choose. You can find a bunch of old manual lenses under $10 dollars to start to having fun with this project over on eBay.