Anybody carry their p226 in single action?

That’s the reason why the 226 is a DA/SA gun. With DA, you won’t have to carry with the hammer ******, unlike a 1911. It’s made to carry in DA. It was intentionally designed for this. It wasn’t designed or intended to be carried ****** so I would consider it a liability. As far as I know (I could be wrong), every pistol designed to carry ****** comes with a thumb safety. It’s called ******...AND locked. 

NO.   The 1911 is single action on the first round so to have it Condition 3 you pull the hammer back and flip on the safety.   It can not fire with the safety on.   The SIG 226 has no safety,  it has a decocker because it is considered safe with the hammer down.   Carry it with the hammer back and you are looking for an accident.   Do not do it.   If you can not handle firing the first round double action then take it to a gun smith and have a lighter trigger spring installed.    Keep in mind the cops in NYPD have guns with a 12 pound trigger pull so they can not accidentally pull the trigger.   By you reducing the trigger pull you increase the risk of an accidental firing and if you shoot someone the prosecutor or plantiff lawyer will love you for it.   I would get a grip exerciser and improve my grip. 

Why can't you change to a lighter main spring (hammer spring)?

I did that on my C-100 Tristar (CZ75 clone) and it made a heavy trigger into a great trigger.

I believe the original was 17# and the replacement spring was 12#. Made a tremendous difference in both DA and SA.

Edit: I have an older Sig 228 that I suspect the previous owner may have replaced the hammer spring on. The DA pull is light and the SA is like maybe 3#, short and crisp. Probably the BEST shooter I have.

The main thing is the main spring.

I own a P226 since the early 1990's and I never carry it with the hammer ******. You are comparing apples to oranges when it comes to the P226 and the 1911.  The P226 does not have an external safety because can be carried safely in DA mode. The idea is for the shooter to be able to fire the first shot in critical situations without having to disengage a manual safety and allow follow on shots to be more precise in SA mode.  It is also intended for the shooter to engage the SA mode if time permits. The SA mode was never intended for carrying and unless the SiG manual has chanced, my old manual states not to carry it in SA mode. The reason is simple: the trigger pull weigh on P226 is very light - it borders on a hair trigger.  If you are in such a hurry that you don't have time to pull the hammer back after drawing the weapon, then chances are you are going to jerk the trigger and fire it when you draw the pistol or discharge it unintentionally before you aim the pistol properly.

The 1911 can be carried with the hammer ****** because it has an external manual safety and grip safety.  And even this is not completely safe because the firing pin is free floating and the safeties do not lock or block it.  This means there exists a chance (albeit it small) that if the 1911 was struck hard such as dropped onto a hard surface, the firing pin due to inertial could poke out of the housing and strike the primer with sufficient force to ignite it. This is why the Series 70's and follow on have lighter firing pins to reduce (though not eliminate) the chance of accidental discharge in the above case.

The P226 doesn't even have a safety, it has a decocker. I'd like to know how a P226 could be safely carried in single action. As far as I know there's no kit. 

I don`t think that kind of carry would suit me to carry 1911 style. Maybe safe in normal circumstances but too risky. The first pull on trigger may seem heavy just messing around but in a tense situation where your life is at risk your adrenalin rush will take care of the trigger with no problem.