Oddly enough, we have made quite a few windows for Google lately, but that $30k entrance was for someone else.
In absolute terms, yes, the house was expensive. However, it's actually probably below-average for Palo Alto. It's not very big (don't need that much space), and building a house does not actually cost that much more than buying one (assuming you can find an empty lot, which I was lucky enough to do).
Even the unique customizations didn't cost a whole lot. There are some cable tubes in the walls, and some custom cabinetry. The awesome architecture was free -- my dad designed it. :) Building curved walls and clerestory windows isn't that expensive; design is the hard part.
In any case, I've been working at Google for six and a half years and spending very little of they money I earned. The savings from that and a hefty mortgage were enough to build the house. :D