Dealing with Private Plugins

You could suggest it to them. If they use one of the popular billing platforms it's not even that hard to implement. Services like Bitpay make accepting BTC really easy, and minimize risk. Fees are usually lower than Paypal's, and the chargeback problem is non-existent.
We're getting a bit off-topic though, so if you would like to continue this discussion, please send me a PM or start a new thread.

EDIT:
Hmm. Realized this is your topic. Not sure how off-topic on your own topic works