Lack of Cup Holders

I have a 1989/90 Sport Nautique that I picked up this past summer. I am getting ready to start my pre 2007 spring clean and refurbish of the boat. I want to add a bunch of cup holder in the pa$$anger side dash as well as along the side rails near the front and rear seats. Is there any problems with putting some on the side rails? Is there material in the way or any other problems I am not thinking about? Anyone have any good ideas or pics of what they have done? Now adays with cell phones, mmp3 players, keys, sun gla$$es, for every pasasnger on the boat not to mention drinks, there is never enough safe spots to put your stuff. Any suggestions?