Anything can be done, for a price. The next question is SHOULD it be done. They are your guns to do with as you wish but in my experience you'll never get your money and time invested back. My suggestion would be to become proficient with speed strips........
If I were to perform surgery on one of mine, I'd probably go with bigger holes rather than more of them.
The answer is it's been done but not recently. I have a Model 28-2 converted to 8-shot .38 Super. But the original barrel did not line up with the 8-shot cylinder, so a new custom barrel was fit also. Mine was built by a custom gunsmith in the mid-90s who has disappeared into the mists of alcohol and drugs. To my knowledge no one is currently doing this conversion since S&W introduced the 8-shot 627 in the late 90s.
You can buy a Smith a helluva lot cheaper than you can have one built!