Is it possible/easy to add downtube shifter bosses to an aluminum frame?

[relyt]

I have a road frame made of 7005 double-butted aluminum. Is it possible to have a framebuilder add downtube shifter bosses to the frame? Or would the walls of the tubes be too thin?

Sorry if this is a common question, I didn't see it in the search.

[Torchy McFlux]

The frame would need to be heat-treated again after welding to ensure strength of the downtube.
Is the downtube round? Have you considered a clamp-on shifter mount? I seem to remember both Suntour and Shimano making ones with bands large enough for oversized tubing.