Shelli,

I think that most (but not all) coleus are short day plants, meaning that short days (or long nights) induce flowering. Since the days are short now (long nights) you might try using fluorescent lights to artificially produce long days for your coleus cuttings, to make them think it is mid-summer.

ZM

I've always over wintered Coleus in pure water in colored
glass containers in an east facing window.I find that when I run the heater the plants resent it so I purposely shut the vents near them so they don't drop all of their leaves.
I replace the water each week,and purposely let it come to room temperature before placing the cuttings back in.I'd always had good results using this method,and the bright foliage looks great when I entertain during the holidays.
I definitely snip the flower buds as they appear as I would during the summer....the blooms always dull the color of the leaves.
Misting the leaves 3 times a week helps them remain lush.
Your zone is a little cooler than mine,but I hope these tips can help you.