On Monday, October 12, 2015 at 11:25:15 AM UTC-7, wrote:
Anybody here have press brake experience? I was to start with 3x3x.375
6061-T6 aluminum Tee extrusion, 4 inches long, and bend up... a Y shape.

T6 is HARD, not gonna bend well (will crack unless you have a BIG radius of bend).
Any extrusion in aluminum is straightened (in tension) and work-hardens somewhat.
A custom extrusion (or semicustom) might be an easier route. I've seen Y=shapes
for rail-riding glides.