Have you seen a mimio? It is small and makes your whiteboard interactive. You use a stylus like you use your finger or pen on the smartboard. It can be wireless and it is portable. It attaches by suction cups or you can use a plastic hanger or even magnets. I take mine down each day. SOOOOOO much easier than a smartboard and does all the same stuff. Oh, did I mention it is cheaper than a smartboard?
I have a SMART board so may be biased, but I really like it. What is good about SMART boards is the Notebook software, and the free resources available on the SMART Exchange website. You may also want to check out Promethean boards too.