Promethean makes a nice product...http://www.prometheanworld.com/us/english/education/products/interactive-whiteboard-systems/activboard-500-pro/
It is available up to a 95" diagonal. Keep in mind that if you get much larger than that many users will not actually be able to touch where they need to on the board to operate it.
Even the Smart Technologies interactive whiteboard is limited in size to (it looks like) 85" diagonal in their widescreen version, which is a testament to how size limited this product really tends to be.
These are all designed for use in a typical classroom environment, so the included projectors work just fine in normal fluorescent lighting.
Many manufacturers will demo their product first hand if this is part of a large installation with 100+ boards to be ordered. If you just need a one-off purchase, then you will have to do the legwork yourself and call the various dealers to see if there is a place you can see a demo first hand.
- Theater, whole house audio, and technology consultation during the build and installation process in the Washington, DC metropolitan area.