10 is a nice age to get a real sewing machine. It might be light weight, but really doesn't have to be. I remember sewing on old Singers and at the time new Berninas by that age. The 50s and early 60s Japanese zigzaggers come in nice colors for a 10 year old girl, I have seen two tone pink, pale blue, mint green. Some of them are all metal and smooth stitchers. There are all kinds of horrid things easy to fall for, Hello Kitty from Janome, miniature zigzaggers on TV shopping channels. I can't think of anything perfect, I would still not rule out the chance of a vintage machine turning up. You just have to take on a bit of cleaning and oiling your self, a full service can come later on if needed. I haven't seen any very nice new machines in the lower price ranges. Maybe a Husqvarna E10 or E20, or a Janome of resonable quality, but to me it feels such a waste to buy something temporarily. Why not just get her something else and hope the sewing machine turns up sooner than later.