-
Not that Pro stems are anywhere near good looking
Well, there's your trouble, and at least half the reason I was being snarky; if you're bothered by aesthetics over function, then there's really no point asking us to help, since we cannot guess what will satisfy your taste.
You should also bear in mind that ±2° is about ±3.5mm height change on a 100mm stem, which might matter if you knew where every manufacturer was measuring from, but you don't. Differences in stack height and measuring references can make more difference than that.
Well, one option would be to JFGI, it's not like 10° is a weird size, and anyway most fits can be accommodated with 6° or 8° and moving a spacer or two.
If you want to spend Thomson money on a -10° stem that's actually any good, try Pro Vibe, although the PLT does 99% of the job for half the price.