While I'm not a big fan of putting a substantial amount of money into a firearm to only change aesthetics in a minor way, it's your firearm and your money. What difference should our opinion have, when the desire is only to "keep it one of the classic SAA barrel lengths". Do you need us to tell you we like a 5 1/2" over 7 1/2" barrel length to justify your subjective opinion or are you really not sure if the 5 1/2" looks better than the 7 1/2"?
I see this all the time on these types of forums....."Which grips look the best", "which color finish should I get, Desert Tan or Drab Earth?", "does a rail really make a gun look cooler or not?". None of this has anything to do with performance, only looks. Sorry, but ugly girls can cook too, and to me, performance, accuracy and reliability are more important to my firearms as to their "classic" look. But again, that's me. As I said before, it's your money and your gun.....you should do what you want and what look you like best, and not worry about what we like. Unless of course you are wanting to sell the gun in the near future with the hopes of completely recovering your investment. Which ain't gonna happen. Your gun is not rare, nor hard to get and relatively inexpensive. My LGS has one for around $500 OTD. You are not taking a classic collector item and ruining it. You may be tho, giving up some performance of the cartridge it is chambered for by reducing barrel length, and thus reducing it's desirability and resale value in the future. But that too should be a moot point, if you prefer the looks one way or the other.