The stock powdercoated cylinders on my 04 XL look sorta "drab" and could use a little bling. I thought of polishing the edges of the fins. Anyone done this?

Your cylinder fins won't get much brighter from polishing. believe it or not, they're already sort of polished. You may get what your looking for though, haven't tried it.

If your real careful you could grind of the powder coat on the fin edges. I believe someone here or on sportster.org has done this in the past and been pleased with the resluts. I would recomend lots of practice first cause it is hard working on those thin edges.

I hand filed the edges of my barrels and heads. Took me almost a month of evenings. Wasn't worth the time even tho they look nice. Machine shops can do the job much quicker.

Thanks y'all.
I was thinking of a dremmel tool with a cut off disk on the side.
Now I have a better plan - to replace the jugs with a 1200 kit!

you could take a sponge brush and carefully paint the fins edge a color to match the bike
thats an old custom trick