Update --
Well I did find one reputable gunsmith who will work on Sigma triggers. The best part about it is that it will not affect your lifetime S&W warranty in any way. The second best part about it is that is totally 100% free, including shipping to and from his shop.
The company is LSG Manufacturing which is the S&W warranty repair facility in Comanche, TX. I totally get the part about wanting to become intimately familiar with every working part of your guns, but when someone out there will do it for free with the blessing and consent of the manufacturer, why not? My SW9VE is on its way to him as we speak.
http://www.lsgmfg.com/
Happy Shooting!
Scott