Hallo Morgan, I have the CV35/1.2, CV50/1.5 and Canon 50/1.4. For me, the 35 and 50 Noktons (not the 35/1.4 Nokteen) look very much alike. I've been looking through 18 rolls worth of slides taken last Autumn with Velvia 50/Provia 400F - colour, and the smoothness you mention seem the same to me, to such an extent that I couldn't tell which one a slide was taken with without having a think back.
I havn't used the Canon 50/1.4 enough to have an opinion on the intricate differences compared to the Nokton, but I have been suprised by it's lovely colours / contrast and lack of flare, I it expected to have a much more olden days character (/flaws). I bought this for my IIIa thinking it's smaller size would be better - but no, it's not all that smaller than the Nokton when you put a 48>>49mm stepup and filter on it. I also find myself preferring the short-throw focus of the 50 Nokton compared to the longer Canon throw.
So, the Canon isn't different enough from the Nokton, and is now for sale and I've got a 50/1.5 on the way to replace it.
If you want the look of your 35/1.2 in 50mm I would go for the 50mm Nokton, remember that these share the same 52mm filter size and you can exchange hoods too.
