The estimate by Wedbush, was exactly that, an estimate. Based on other sources (notably,
Opening the Xbox, which went into detail regarding the contract prices from the heavy hitters (intel, nvidia, DVD, HD,etc, as well as some other analysts reports), the cost are probably a bit higher.
Given that Microsoft's loss seem to be much more than the shipments of their hardware, the loss they're taking on the hardware is only a small part of their overall losses. This is based on the fact that they were able to lose $1.1billion on revenue of $499 million. Consider that their revenue includes hardware, first party software, royalties from 3rd party software, and Live subscriptions, they seem to have been able to lose at least ~4 times more money than thier hardware sold for. Looking at it another way, if they gave away the hardware for free, their losses probably would have only increased by only ~$300 million or so (assuming the same hardware sales, except for the fact that we all would have taken dozens of free xboxes

)