Remember that updo you gave up when you went short? It doesn't have to be that way! If you've got your heart set on a bun, French twist, braid or chignon for a special occasion, hair extensions can make it happen.
You can get ones for cheap, but this might be a place to splurge if you want the look to seem natural (and elegant). Many salons do hair extensions, and they can blend right in when done well. You may find you want to keep them in and wear your hair long for a while -- change is such a good thing.