If you take away one thing from today's commentary, it should be "don't pull this stunt on your underwriting manager." WATCH THIS VIDEO , it's worth 30 seconds. The jumbo market is taking baby steps in the right direction. Redwood Trust Inc . is marketing a $280 million residential mortgage-backed security, the first private deal of this year, backed by a mix of fixed-rate and adjustable-rate mortgages. According to news on the issue, the average loan size is $978,000 and the average FICO score is...