Okay, I'm going to share with you guys the ole tyme' gunsmiths way of dealing with this, and I suspect that a lot of you won't like it.
First off, and easy way to deal with this is to purchase a take-off barrel (used) that is being sold because someone wanted one longer or shorter.
But, there used to be quite an industry (before cowboy action shooting even existed) for accurizing SAA pistols with problems just like this.
The pistol was shot by the gunsmith from a rest to get an idea of what was going on with the barrel.
Once it was established that it was a barrel issue (as opposed to something simple with the sights), it was placed in a jig on an arbor press, and the barrel deliberately (gently!) bent to compensate for the direction it was shooting off target.
And yes, this was done for Colt factory pistols too.
The pistol was shot again, and finally regulated for a distance that was accurate from 0 to 25 yards.
There are a number of articles in the old gun magazines and Gun Digest from the 70's about this. Funny that it's not mentioned much any more. The bend is so subtle you can't really see it with the naked eye.
That's what I'd do if it was my pistol. A replacement barrel doesn't cause any cringing however.
G.