How large do you want the print? Because you're not going to find anything on the web that will produce a huge print cleanly. Your best bet will be to contact the Pens PR office and ask them if there's a photo you can use for that purpose. They're likely to have the largest, highest quality file you will find. That or they will put you in contact with the actual photographer of some of the more famous shots and you can buy a print from them.