I sometimes use my roadbook holder as roadmap holder:
ofcourse... you'll have to copy/cut (parts) of the original map such that they fit your roadbook.
Mine's an ingenious one: you don't have to tape sheets together; just shove them under the foil.
http://www.chalmet.net/
This instruction video shows how it works:
http://www.chalmet.net/images/handleiding.wmv
HJ