Boki Miniatures has done some Naps in true 8mm. Adler are close, I believe, although Mr Adler would take exception. Baccus have tall bases, they are bigger looking to me than 6mm, especially compared to the original 6mm, Heroics & Ros, which is closer to 5mm.
The growth of smaller scale interest in recent times hopefully will allow you to find an option. And yes scale creep is all over the place, so watch out! RB