For me, it is 1.2 to 1.3 cpm. I would be a buyer at 1 cpm. And I would, without hesitation, sell all my miles to you at 2 cpm (if it weren't against the rules).

I actually used a spreadsheet to come up with this estimate. I did what AS219 said, which is to first determine the best (and most likely) use of the miles. In my case, this a high-season long-haul F or C award, after I already have 1K status. Then I honestly estimated what I'd pay for an equivalent (same restrictions) mileage-earning ticket. Don't forget to subtract out the cost of taxes/fees (~$50 for a 1K), the value of the EQM, e500, and RDM (which is circular, because you need an estimate of the value of RDM in order to estimate the value of RDM)!

Based on my spreadsheet, and a LOT of assumptions, here is how I would value miles, depending on how much you'd pay for a real long-haul F ticket to Asia (assumed to be 20k BIS miles):

$1900 : your value is 1.0 cpm**
$2300 : your value is 1.3 cpm
$3000 : your value is 1.6 cpm
$4000 : your value is 2.2 cpm
$5000 : your value is 2.8 cpm
$6000 : you're rich and I hate you

If anything, I think these are overestimates. I assumed that the value of (not) earning EQM, e500, CR-1, MM, is $200, which might be a bit low for most elites (except after already locking in status for that year). Of course, it's too high for non-elites.

** You, my cheap colleague, are better off with a penny-pinching Y or C award, in which case your value could go back up to 1.3 cpm.