You get 42" versions from China for USD$118 each. I'd focus on the software improvements and benefits.

http://goo.gl/N02wRa

you could probably connect this to rPi to make it smart/connected.

It's probably using some no-name USB HID driver so yes, it will look like a mouse to a Linux system as long as the udev tables match up. Might need some tweaking to handle the multi-touch stuff.

I wouldn't say it requires a projector or smart pens. My school had both the "official" smart board most people know, but also a model of whiteboard that used IR sensors and regular pens.

I don't know how expensive they were, as they still were a commercial product sold to schools, but they didn't need a projector or smart pens

I forget the name, but I worked at a place ~1997 that had one that I'm pretty sure used regular board and pens. It had two bar-like devices affixed to a side and along the top of the board.

I remember that product. It seemed like a good idea, but it just couldn't keep up with writing at normal speed so we gave up on it. (You also had to put a special collar on the otherwise normal markers.)

Yes, the collars! I remember it had a kind of kiddie-name and maybe some blob-type design elements.

Ah, this is a key piece of information, and indeed sounds like quite a big deal.

You should mention it in your presentation!