Hi cchu518,
There are plenty of good information posted by other members. First thing, check S&W forums there are plenty of good information on these forums and a good chance of finding reasonably priced model 19 for your wife.
To pick a good alternative for model 19, ideally it would be great to know what your wife is planning to do with it.
4-5” barrel revolver chambered in 38/357 is a well balanced do-it-all gun. S&W model 686 will be an excellent choice, it is available in different finishes, and Plus models will have 7-shot cylinders. This revolver is well known by gunsmiths and there are plenty of aftermarket parts. I shot heavily modified 686 in PPC competitions and it performed extremely well. Another solid choice is Ruger, plenty of models to choose from, those revolver are built like tanks. In recent years Colt brought back its popular snake-series revolvers such as King Cobra and Python. There were some issues with earlier models but from what I heard those issues were fixed.
If it is a carry revolver there are plenty to choose from S&W makes plenty of compact revolvers with 2.5 or 3 inch barrels, Ruger makes plenty of compact revolvers. Kimber also makes very good compact revolvers. Majority of modern compact revolvers are capable of handling 357 Magnum loads but it is not very pleasant experience to shoot those.
Lastly, if she wants more of a range / target gun it will be hard to beat 6 inch revolver. These guns are more muzzle heavy and it might take some time to get used to it but besides that 6 inch barreled revolvers are fantastic shooters. Extremely accurate and soft shooting guns. Hopefully you will be able to find the perfect revolver for your wife! Keep is posted!!!