Is 37 too old to start MBA?

Ph.D from a top 5 engineering school in the US. Lots of
patents and publications. Worked for 8.5 years. In my spare
time I did an invention on my own, sold it to a company, and
paid down the house.

Currently taking a very stable technical job in a mid-sized
silicon valley company, making $230k in total,
with roughly $1.4 million in total assets.

No upside potential in the near future. Bored by the daily
technical chores and looking for a mid-life career boost.

Just took GMAT and scored 760. Considering doing an MBA
in a top business school (Harvard, Yale, and Stanford ...)
starting 2008. I will be 37 by then, and will be 39 at completion.

My questions are:

1: Is 37 too old to start an MBA and a life in business ?

2: How is the likelihood that I will get admitted by those schools,
given that I have no business background?

3: What can I do with an MBA at close to 40? Can I still start a
career in the financial industry, like Wall Street? Bored by high-tech.
No too interested in doing starting a company.

Serious replies from professionals only please!