I'm developing some user interfaces for big displays. A lot of them support multi-touch interaction. I started to draw some mockups manually with pen & paper. For various reasons I want to do it with a computer in the future. First of all, it is easier to store it and I hope that there are some programs that support me in copying various user interface elements that I need multiple times.
So my question is: are there any good programs that can support me in the creation of mockups of "non-traditional" user interfaces?