Try armen @ digitalww.com He has touch overlay kits. I'm not sure how big though, but this will point you in the right direction hopefully. I think ELO sells touch overlays also.
I remember a long long time ago in the public library's children's section there were crt monitors with touchscreen screens that were put over the CRT's display(it looked like an antiglare screen)
I was wondering whether they still make something like this because I have a lifebook which has a 10.5inch wide lcd in it and was considering maybe buying a touchscreen for it if they even exist.
Anyone know of any place that sells something like this?