Forgive me but this is a pissy post, haha!
I've converted some regular bras into nursing bras. It's really not very hard. I probably wouldn't do it on the new bras that you really like, at least not at first, but maybe you could pick up a cheap bra that you don't hate and then try converting it? That way you'll know how it goes and you can decide if you want to do it on a nicer bra, but either way maybe you'll have a bra that falls somewhere in between the bra you love and the icky nursing bras. I wore nursing bras pretty much till James weaned, so I feel your pain. I know towards the end he was going long enough between nursing that I would wear normal bras and then pretty much only nurse him at home. Depending on the cut of the bra I could also sometime get my nipple out without actually removing the bra, but it sounds like that doesn't work in the bra's you have.
You probably don't really want to know what my lovely 38 H (maybe I) boobs and I are doing.