I am not an engineer, by any stretch of the imagination. With that
caveat out of the way, I would be leery of mechanically altering a firearm intended for HD or SD. My reasoning is that it doing so could contribute to a malfunction that would either: (1) cause it to go click when it ought to go bang; or (2) cause it to go bang when it ought to go click. Neither strikes me as a desireable result. If we're talking about a range gun, that's a different matter altogether.
If I were determined to have a gun with many of the same qualities as a Glock (reliability, decent capacity, polymer frame, what have you), I'd consider the following, all of which (I think) are available with thumb safeties:
- XD/XDm/XDs/etc.;
- SR series;
- M&P series