Yeah it seems likely the cpm is going to be close to 1cpm (if not equal to). Keep in mind the Delta transfer miles promo that was going on recently was effectively 1.1cpm I believe, without having to sell items on eBay and do the legwork that this promo requires.
Last time I think I came out to 0.45cpm or so, which for me is on par with the US Grand Slam in terms of cost but without the huge number of activities required, so it was actually a better deal.
Let's keep our eyes peeled for new additions to skymall this week, and maybe there are some other creative items. I noticed they have the walking stick of Lucius Malfoy which I can't find online for less than MSRP ($95) so that might be option. If not that, then something in the "collectibles" category.
If my projected costs are above 0.7cpm or so I'm gonna sit this one out. It's a shame because given the right conditions this could be an amazing deal: (a) you live in a state with no sales tax (b) there's a new electronics gadget that can't be bought for lower than MSRP elsewhere and (c) you have a channel to sell them that doesn't have fees.
I got 100k last time but if someone could meet (a), (b), and (c) above I'm sure you could clear several million miles for around 0.2cpm.