Upload & Sell: Off
I would say that "issues" with colors comes from digital making everything from:
1) interpolated colors (exception is Foveon)
2) only RGB (certain films had 8 layers of colors, not sure how much current Velvia does have or how exactly it works, maybe less, maybe different, but still seems to be good)
3) colors are saturated different way, even very saturated films seem to have sorta "natural" saturation, over-saturated digital looks like exactly what it is - over-saturated
When printed (especially if its old way printing, I think its called contact printing in English?) difference is much bigger than when viewed on display.
Grain is another matter, in most films it doesnt matter, its just sorta part of it. Noise in most digitals looks just like something that shouldnt be there at all (expections are, but about as rare as those with good colors).
I think digital could reach something similar, if colors were non-interpolated and made from RGBCMY. Which is currently most likely impossible, so I would say maybe 80 mpix digital back with special CFA, could do that trick. I would probably try to merge 6 color pixels into one, to prevent interpolation. Which would result in 13 mpix image, most likely crazy sharp and with good colors.
Tho someone would really need to be pretty crazy to do that.. Wonder if it would really work. Most likely it would hit color limit with most monitors and printers anyway. Thats another issues too..