I think there might be a disconnect here considering the question. The answer is simply 1.
Let me explain to you why, since the question reads to me like you are missing the essential purpose of it all.
"Stealth" is to go undetected, unnoticed. Therefore, the concept is simple, 1 ebay account per paypal since the idea of this entire thing is to be viewed as different people. Once you link 2 accounts, you are essentially telling ebay/paypal you are 1 person, not 2.
So the comment "I don't want the trouble of making and verifying a new paypal for each eBay account" tells me that either you do not understand the reason for using stealth, or you do not really have a need for it.
If you are doing "real Stealth" then not only should each ebay account have its own paypal, but each user should have its own IP address.