I know of 3 automotive machine shops, that are semi local. All would rather sell me a Scat or Eagle crank than to do any crank work. None do crank balancing.
I've asked elsewhere, what it would take to convert a 360 crank to neutral balance. I'm not wanting to buy a crank if mine is perfectly serviceable unless I was doing a stroker. Further I don't know where I would have to take it, in order to have any sort of balance work done. but if I have to take my crank elsewhere to have balanced that means I'd have to have them do the whole machining job. The shop I use does a great job at a fair price, for anything else. They do send any crank work (beyond a basic polish) out, I do not know where that would be.