aspdaddy - 4:38 pm on Mar 5, 2011 (gmt 0)
I have a retail site where 15min of downtime can cost the client thousands and the afiliate programe fraud is rampant. Its got similar challenges to yours.
What you dont want is some expert who can firefight these issues continuosly. What you need is a high availability and secure design and BCP that you expect to execute, log shipping, warm servers etc.
I'd look for someone who is very calm under high pressure and and with good infrastrcuture / data centre contacts