Using your zipper foot and a size 16 or 18 jeans needle, make a tuck above the hem in the jeans.
When measuring, remember that the tuck should be HALF the amount you want to take off. I try to sew under the the little top of the hem.
This is what it looks like when you are done - notice original hem still intact. After trying on AGAIN (measure twice, cut once), I trim the seam, zigzag over it, put fray check on the edge of the seam. Press what remains UP.
Voila! You have jeans the correct length, but still have that factory finish that you can never duplicate at home. I read abouit this technique somewhere -- it's how professional tailors hem jeans.
The first couple of times after washing, you may need to press the hem up. Eventually, it stays on it's own.
If I had growing children, I might try this without cutting the tucked fabric (if it wasn't too much). That way, you could let them down maybe 3/4 to 1".
I don't know why I hadn't heard about this before. Or, thought about doing it myself!
This takes me about 10 minutes or less to do -- maybe 15 with trying them on twice. If you grovel, I'll hem yours for a Diet Coke.
This is the view from the hall way as you enter the sewing/office/scrapbooking room.
It's bad. Really bad. So far, I have carried out over 5 big trashbags to give away; and probably 2 of trash.
Using your zipper foot and a size 16 or 18 jeans needle, make a tuck above the hem in the jeans.
This is what it looks like when you are done - notice original hem still intact. After trying on AGAIN (measure twice, cut once), I trim the seam, zigzag over it, put fray check on the edge of the seam. Press what remains UP.
Voila! You have jeans the correct length, but still have that factory finish that you can never duplicate at home. I read abouit this technique somewhere -- it's how professional tailors hem jeans. 
