Same here. I filled out only 1 rebate form for 4 packs and the Outpost CSR said that was fine. Well, it certainly seems longer than 4 weeks to me, but at least I got my rebate, just today. =)
I think it's one rebate per address, but I personally wouldn't want to go through all the trouble and wait so long for the rebate. At least back then, I had the $10 flooz deal.
By the way, the CDRs label "1x-4x" compatible, so I'm not sure about burning them at 12x.