Went ahead and e-mailed clack asking to confirm that he's received my change of address, will let ya'll know if he replies/is alive. If he doesn't, then I'll probably stagger sending PMs to both forum names and then to a couple e-mails he has associated with Paypal. Kind of need a reply or update at this point, since I've reached the point of no return on my address.
I will say that it's not unreasonable to expect some minimum level of communication from someone in a transaction, especially when that person has collected money from over 100 people through Paypal. All it takes is a few of those people getting nervous that their money is being mishandled and opening a Paypal dispute, and next think you know the seller's account is placed into the seventh circle of Paypal hell. And imo making a post somewhere that says "I'm sick/life sucks/work sucks/had a kid/etc., here's my goal for fulfillment" (like sprit has regularly been doing now) is much easier than proving to Paypal that you're not a deadbeat and having your account under withdrawal restrictions for a year+.