Yes they are becoming more and more of a good alternative to projectors and boards.
Firstly we have had a few demo's of dual lcd touch screens and those built for education have fantastic resistant screens, have literally smacked them and their toughness is impressive.
While the prices are high, the life expectancy of them is making them a long term viable option.
You can get various sizes up to the size of most IWB's so that isn't an issue and there are ones that tilt to lay flat so groups of kids can gather around and interact with it as a group.
Personally we believe for a fair number of schools this will be the future, due to the features it offers and the life expectancy of a unit.
I would say they are a great option for primary schools but a risky option for secondary.
I have just been told that Sahara are currently pushing Dual LCD'S and Demo'ing them to their primary customers, and looking at their product range they are investing in this on quite a large scale.