Maybe one or two people don't have credit cards, but I can't imagine that's common. Maybe it's possible to set up PayPal accounts without a credit card in some places, but in 2 countries I've lived in you need a credit card for PayPal. No direct debiting from your bank account. According to the above, that's not true in the UK. But I've usually assumed people using PayPal already have cards. So - I don't know for sure, but... - I'd guess you wouldn't lose much custom switching to credit card payments. Or why not accept both PayPal and credit cards?
Incidentally, my wife exports clothing via the internet and also complains about PayPal - the fees and also a few customers who, despite no wrongdoing on my wife's part, have made 'claims' against her, freezing up her account. She also accepts bank transfers and will collect WesternUnion transfers.
I wouldn't want to buy from you via bank transfer, though, Maxim. Bank transfer fees for me from Korea aren't as high as the guy above, but it'd still cost me $20.