A 3D-printable variant of BitBeam, this is a parametric Technic-compatible beam. Specify the number of holes, render it to an STL in OpenSCAD, and you're ready to print. Unlike BitBeam, it does not have holes on all sides, just top and bottom.

Open mybeam.scad, scroll to the bottom where you see "beam(15);" Change the number in parentheses to the desired number of holes. Choose Design→Compile and Render, then choose Design→Export as STL; Once that's done, you can print the STL.

Some other items of interest:

• angle_lever.scad: It's like mybeam.scad, except you can create objects like the 4x4 technic-compatible lever.stl attached. Change "angle_lever(4, 4, 53.5);" to whatever you want.
• bush.scad: Use this to create bushes and half bushes. Change "bush(beam_width, 3, 3);" to whatever you want. When you print it, you'll need to break off the little tabs ("mouse ears") that hold it in place.
• gear.scad. Use this to create gears. Change myGear(number_of_teeth=40, holes_row=4, holes_col=2); to whatever you want. Requires gears.scad from MCAD (https://github.com/D1plo1d/MCAD)