I need a header to span a 16' opening in an interior bearing wall, with a floor and roof overhead. The width of the house is 27'. I need to keep the header under 12" tall, but I can go up to 9" wide. Can I achieve this with LVL's?

From what I had discussed and my subsequent calls to three manufacturers,no.

Even tripled up 11 1/2 inch LVL's wouldn't compensate for this amount of load bearing.

The suggested I beams in either side of the existing wall seems to be the correct solution.You will still have some drop in the ceiling and the pipes will still need to be there for the cold air returns.

(PS, if this is the same customer I am thinking of,, :p, the question is too similar to the job specked here a week ago)