Question-see text:

[M67A2 Zippo Tank]

Does any firm make a reputable Colt Python clone with the si barrel?

[Dave Berryhill]

Does any firm make a reputable Colt Python clone with the si barrel?
No one makes a Python clone.
What's an "si" barrel?

[M67A2 Zippo Tank]

LOL, I meant six inch barrel.

[SquarePizza]

While there are no "clones" so to speak, there are cheaper options that are similar.

First the closest would be the King Cobra, which has similar lines to the python. It was one of Colt's later revolvers so it was less hand-fit, but still desirable and well built.

The other alternative I would say would either be an N-frame smith and wesson (the Model 27 was the Python's comparable of the time), especially one with the target trigger and grips.

Or a S&W 686, which has the underlug, but lacks the factory smoothness of the N-frames or the Python.

[anachronism]

Heck, nobody makes Colt Pythons either!

Try a Ruger GP100 with a great trigger job. The hammer travels longer than a Smiff, but it'll last a lot longer before needing a refit, and accuracy is surprisingly good.