We get faced with this too. You have two things you could do...
1. Build up your stock for the show, but only list one design and not the lot.
This option allows you to list new designs/products and see how popular they will be, then what you don't sell at your show you list on Etsy.
2. If you want to build your presents on Etsy, list your items and then deactivate what sales at your show. You will have to closely watch your sales on Etsy everyday of the show. This option allows you to only loose what you sold and not de-listing everything and then have to re-list if it hasn't sold. If you have an iphone, you can watch and de list right from your phone. They have etsy apps.
This is what we came up with, if you come up with a better approach, pass it on!