There are all sorts of cheesy stained glass contact films of all sorts of colors at your Local Home Center (as The New This Old House calls it), but Matthew can best answer where to get plain old frosted white vinyl.
I'm not sure where I saw this, whether it was reality or a dream... but didn't somebody cover their windows with the translucent onion skin of a dress pattern? Was that the slope house again Matthew?
I think Anthropologie used a similar treatment one or two years ago -- not on thier windows but inside as curtains in their retail space. The effect was very feminine and lovely but also industrial and no-nonsense.
Or you can really go DIY and print out the exact hues you want on overhead projector acetate on your home printer.
I will admit this is one of the most hilljack installations I have ever made, but nobody ever lifts the white blind, so its just an illusion.
Total cost: $35.
Total effect: priceless.