Typically a 1911 shooter, I've been looking into purchasing a P220. I've always like the style and unique look of the Sig and since I significantly prefer the .45 over any other pistol round the P220 is the one. After shooting a Sig that belongs to a friend I found that there are only two things that I really don't like about this particular model. 1) Being a lefty I'd greatly prefer the de-cocker to be on the right side. 2) I like a trigger that is significantly lighter, both DA and SA, than what comes standard on the P220. The de-cocker, well, I can live with that. But I would find range trips much more enjoyable—and might feel better about throwing down a grand + to buy one of these babies—if I could lighten that trigger up a bit? Is there a trigger kit out there that will do this? Better yet, does someone know of a gun smith with experience in this area? It seems like I tracked one down on the internet some time ago but am now unable to retrace those steps. Your input is much appreciated.

No personal experience, but Gray Guns comes up all the time on here as a great Sig gunsmith, and he has trigger packages.
Sig offers the "Action Enhancement Package" as well as the "Short Rest Trigger".  Sig  I had both done on my p229 and like the trigger, but it had been a while since I had shot it and sent it in so I couldn't get a real great idea of "before and after".  I don't think the "Action Enhancement Package" lightens pull, just smooths it out.  Gray Guns package appears to smooth out, but can also lighten pull.

I put a Wolff brand 18lbs hammer spring in my M11A1 to lighten the pull.  I'm pretty sure that Wolff makes springs for the 220 as well.  Cheapest route.

P220 SAO?

This ^
No de cocker, if you did not know sig have a changeable mag release to both sides. And the safty is ambi so it's a win win for you my friend.

If your a 1911 guy look the SAO sig, I think they make an x series in 45acp.