I haven't, but I like homey things like this (need to get Mason-Dixon Knitting). I have seen patterns, but I can't remember if they were for knitting or crocheting - a lot of the pattern books have both.
My knitting instructor had crochet edging around her windows - not too fine of a yarn, but very pretty. I was thinking you could use just about any lacey pattern (like a lace scarf). I tried looking some up at knitting pattern central, but all I see are 'tidies' and this valence. Or if you need something non-lacey, you could just look at different stitch pattern textures, or even just do simple stockinette stripes.
oh wait , under miscellaneousat knittingpattern central, (no picture).
I have some windows that need curtains, but they're big windows - I think it would be better for me to use fabric. Though a knitted border might look really neat...
You should try and knit some for your windows!