hmm no matter how you reason it, its still a rule 
that paypal and ebay has..as most credit card 
companies do too. Its illegal to pass on the 
extra fee to the customers. If you think i'm 
joking, then just check out the list of rules on 
ebay because its there. what you are allow to do 
is charge extra fee for *everyone* but you can't 
charge extra for just credit card people. 

Payment Surcharges
An eBay seller may not charge a fee, often called 
a "credit card surcharge," when accepting credit 
card payments. This surcharge, which is an added 
cost to the buyer over and above the final sale 
price and shipping/handling, is not allowed under 
the laws of many states, including California. 
For more information, see: 

http://www-
s2.visa.com/fb/merch/biz/govt/surcharge.html
http://www.mastercard.com/consumer/cust_serv.html