I've checked TGS, Brownells, and Numrich, but all the 8mm triggers I'm finding are serrated. I like the serrations on my 10mm wide P226 trigger, but find it a little rough on the 8mm trigger. Anyone have a source, or do I need to smooth it out myself?

Ebay has a couple of 8mm triggers by TJ's custom. Only problem is that they are short trigger style.

o5

The only smooth 8mm P220 factory trigger I am aware of was the “short reach” version. Of those I’ve seen, all appear to have been modified from standard grooved triggers.

I tried a short reach trigger in a P229 and didn't care for it. I can't imagine that would be any different in a P220. Guess I'll look into smoothing and refinishing a serrated one. Would Birchwood-Casey Permablue work for that?

JAFO,
I don't know how adventerous you are but several years ago I posted the results of an intellectual exercise I did in which I trial installed a P239 trigger in a P220. The text follows, however, the photos are held hostage by PhotoBucket.

Answer to P220 Trigger Question That Nobody Asked
There have been a few threads here where I have read members grousing about the grooved trigger in the older P220s and the P220ST. I own one of each and don’t mind the grooved trigger, but I digress.
While detail cleaning my P239, it occurred to me that the P239 trigger looked very similar to the narrow P220 trigger, except that the P239 trigger has a smooth face. When checked with my metric scale, the P239 trigger measured 8mm wide just like the P220 grooved trigger. That got me wondering if they would interchange. So I removed the trigger from my P220ST, and this is what I found: Both the P220 trigger and the P239 trigger have exactly the same size holes for the trigger pivot pin and trigger bar pivot. I placed both triggers side by side on the P220 trigger pivot pin to compare alignment and overall profiles. I observed that the trigger bar pivot holes are slightly misaligned and the triggers have somewhat different profiles, yet they are very similar.
Now more curious than ever, I proceeded to reassemble my P220ST with the P239 trigger and did so without difficulty. Then I chambered an A-Zoom dummy round and dry fired the gun several times in SA mode with no problem. I also did a DA dry fire, and that worked as well. This certainly was not an exhaustive study and I am not recklessly advocating this trigger swap based on my single sample. But, for those who would prefer a smooth-face trigger for their P220, you might want to further investigate this for yourself. It seems to work.
In the following photos, the P220 trigger has the grooved face and the solid back, and the P239 trigger has the smooth face and the hollow back. Both are mounted on the P220 trigger pivot pin and the P239 sear pin is being used to illustrate the slight misalignment of the trigger bar pivot holes.

Tempting. Numrich has both triggers, but the 239 trigger is more expensive. There's only ~$3 difference between buying a 239 trigger vs a serrated 220 trigger plus a cold blue kit from Midway. I suppose if the 239 trigger didn't work I could always sell it and get go try smoothing a 220 trigger.