bounce light as a structural object

In a show that I am currently designing, there are three sets of columns that hold up headers which span the width of the stage. Each of column/header has a 6 inch slit on the onstage edge out of which a soft even light needs to pour, without seeing the source.

after much discussion with mark and others, here is the proposed solution. those are 1k pars---now if i can only find enough!

I think it will work. If the interiors are painted white, there will be tons of light bouncing around--some of that 1k power is bound to come pouring out. And when it does, boy will it be even and pretty!