Well in the 30 seconds I searched google, it seems google produces the Nexus 7 for $152.**. Selling them for only $48 profit. Here is an article explaining that they are in fact selling it for just above cost.
Google Nexus 7 developed in just 4 months, sold essentially at cost price | Android Central
I however do not have info on the cost to produce the phones, but with them releasing a 32GB Nexus 7 with HSPA+ connectivity, (basically a 7" GNex) for $299, I still don't see much profit. Sure its more costly to include the HSPA+, but how much? So no, I don't know, but I can speculate. My reasoning to think that they aren't concerned with making money on devices is based on that with lower price points, it attracts customers to the Android ecosystem. Once they have an android device in your hands, they make more money in ads/app/book/music/movie/tv etc.. sales to compensate for the low priced devices. I'd also speculate that T-Mobile will probably drop the price around thanksgiving. And I don't think we'll see a VZW variant for a while.