Bank examiners are employed by state regulatory agencies, the US Treasury OCC and the Federal Reserve. There's a few thousand bank examiners nationwide; the Fed is most concerned about top-level banks.

One thing to keep in mind is that in this recent (last 10 to 15 years) run-up, there has been an explosion of non-traditional mortgage lenders, especially in places like California (the fount of all that is stupid of recent - if something is especially stupid, odds are high it was done first in California and made fashionable there).

These non-traditional lenders were not "banks" and didn't have "deposits" - and were not insured by the FDIC. They originated tons of loans, many of them non-traditional loans. They obtained the money to originate loans by selling securitized mortgages on the bond market(s) around the world.

As to the LTV level, here's a good historical view of the issue, a tad long, but then it reviews LTV's going back to 1913.

http://findarticles.com/p/articles/mi_m0ITW/is_10_86/ai_n14897523/pg_1