They suggested I set up a brokerage account somewhere and transfer the shares directly to that account, in my name, which could be done 1) for free and 2) in 5 days, without waiting once again for the address update cycle. Since one goal of this is to trade a share of HPQ for some small number of shares in XM Satellite Radio, I'll see if I can accomplish that. Once that's done, then I'll get the shares issued as a stock certificate, just so I can hold it in my hand.
In the meantime, I called HP and got my address updated with them. They couldn't tell me why they were still sending my name and address to the plan administrators two years after I'd left the company, though.