Try as I have, I've not been able to find a way that converts colour negative to positive as well as ColorPerfect. It is a strange situation really, in that there seem to be few satisfactory options, certainly outside the the realm of Adobe centric solutions. The method of manually dividing out a film base sample from the image, and then using adjustment curves gives an odd looking image to my eyes.
I was looking through some of my old C-41 contact sheets yesterday and the colour quality is excellent in most cases - this was on the discontinued Kodak Supra Endura paper.
I started a ColorPerfect user group on Flickr long ago. It's not very active now, like most of Flickr. But it may be worth posting there.
https://flickr.com/groups/colorperfect/