Could Colt offer nitrided versions of their stainless steel models? I don't know much about the metallurgy of this, but a very brief Google search made it seem possible to nitride stainless steel for a blue/black (dark) finish. If so, then this finish could be offered without requiring new non-stainless parts or, possibly, additional polishing beyond what's currently done. Not the same as the old Royal Blue finish, of course, but if possible, it could be another option.
Nitride is a possible option.
My buddy has his Bartline match barrels nitrided and they come out black.
I assume that if the stainless is polished the Nitride would have a shiny finish.
Colt obviously has a method of blackening stainless since they're offering at least one model of the new Cobra in a flat black finish.
The problem with a shiny blue-black Python isn't what type of finish that could be done, it's the polishing of the metal.
The old Colt Royal Blue as used on the Python was 95% hand polishing. The exact same type of bluing chemicals were used on all other Colt models and is used by all other gun makers.
It's the high level of polishing that gave the Python the blue mirror look, and that takes a highly experienced worker.
That level of people don't work for minimum wage, and the cost would put the price VERY high.