PayPal Plugin?

I am planning on writing a PayPal plugin because I haven't seen one out there yet. 

I'll try to make it extensible but for my purposes it just needs to be able to accept payment for different account types.  I'll have a "free" account with limited functionality and then two other account types that cost money.

I found this group but they don't seem to be doing very much:

Is anyone aware of an existing plugin for receiving PayPal payments through Elgg?