Surprisingly, on the forums I don't see bitcoins mentioned much, but I think it would be a good idea to accept bitcoins so people can buy plexpass with it. For those unfamiliar, bitcoin is a digital currency already accepted by big companies such as Expedia and Dell.
There are payment providers which make it easy to accept bitcoin. You can even choose to receive dollars from them. The payment process is easy to implement (quite similar to paypal) with a payment provider such as coinbase ( https://coinbase.com/merchants ), though there are probably more.
Accepting bitcoin for PlexPass Lifetime would probably be quite easy as this is a one-time payment.
I have already heard of friends wanting to pay for PlexPass in bitcoin and I have seen this being requested on the forums as well.