You can absolutely make the leading edge much more aerodynamic and add just a tiny bit more weight. First of all, like Peter suggests, you do want to retain the original tube, same size and everything. But like Billie mentioned you add additional structure. The key point is that you can make a shape bigger and have huge reductions in drag. A pure cylinder is about as bad as it gets in regards to aerodynamics and I don't think we are getting anywhere with double cylinders. Still not efficient. So we have the original tube the same, holding all of the structure, but when we add additional structure what do we make it out of? Easy, just make it out of some super light compressible foam, that you can press a finger on it and it will fold up, but what it will do is create a better teardrop structure. If you look at an old school VW bug it is about half the size of a modern compact car yet pulls through the air like a mattress, coefficient of drag of .5 and a prius though ugly looking and twice as big as an old VW bug slips through the air with a coefficient of drag of .25.
You want to think about just adding more size to that leading edge and then you'll get dramatic improvements in aerodynamics. You don't want to make it smaller or sleeker with double tubes and such but to make it bigger by crafting light weight fairings that have no structural strength but add greatly to performance.
This would be a fun DIY home project, sewing on extra fabric to the leading edge and trying out new shapes or throwing the new shape on a computerized air tunnel.