CLifford... we always specify IAC STC-51 2 1/2" sound doors. They are EXPENSIVE, but installed properly they work like nobody's business... Expect to spend at least $3000 for each door. Glazing not a problem... If you're looking for a DIY solution, then it comes down to a good thick door leaf, double on the glazing (with as wide an air space as possible) and, most importantly, getting a good seal ALL AROUND the door... I've seen so many massive expensive doors installed that leak like swiss cheese because they do not seal well!! that's the ticket!! There are many ways to seal them, but ZERO seals or some good quality equal is typically the best. A good set of ZERO seals will run you over $500 per door opening... just be advised. It's not cheap to get good door performance!!
