That thing is scary.
2 layer boards are so cheap (qty 3 for $1.67/squinch/each), why bother, though?
Especially considering you are polluting the environment with your improperly disposed of chemicals in a home-etched setup.
Only real men skywire BGA's.... totally crazy.
If the pitch of the BGA is too fine, you can't break all the signals out in just 2 layers. On designs I work on, this is the only reason some of my 6 layer boards end up as 8 layers.
In his case, a little TLC and some time can probably get em all out in 2.http://pcdandf.com/cms/images/stories/mag/0708/0708ali3.jpg
Whos got 2 layer for $1.67 / square inch? I assume no mask, no silkscreen. I also assume probably some upfront tooling cost. That or one of those share a panel with other design kind of places.