Start with the bad....
The LeatherLyke saddlebags cost $460, plus tax, shipping, etc..
The rest against the rear springs with a nylon rub strip. After 3.5 years of rubbing you can see the chrome worn:
The good:
You asked for detatchable and lockable:
http://savage.andruschak.net/Paladin/LeatherLyke_off-on.AVILess than 30 seconds to unlock remove, oops didn't mean to, install and lock.
After four years of near daily use they still look and function very good.
They are designed for the Savage, install with all parts supplied and without needing to do any re-engineering, including the relocation of the rear turn signals.
They are spacious enough each side can take a five-liter box of wine, or two one-gallon jugs of milk, or a ten-pound bag of potatos, a rolled up leather motorcycle jacket, etc.. (It sure is nice to be able to shed the jacket when the day warms up.)