If there's interest in this, I can relay donations via PayPal from my German bank account. I would however have to take some commission (5%?) because of the manual labor involved, in addition to the PayPal fees.
It would be cheapest if Wikimedia itself could process credit card payments directly, although I don't know how complex the necessary software is. There are a lot of CC processing companies, but some of those may end up being as expensive as PayPal.
Regards,
Erik