First of all, let me say this dress is gorgeous. The time involved to make even one of these dresses, much less multiples of them is amazing.
1) Enter them into your local county's or state's fair competitions.
2) Contact local museums (historical, town, fiber arts, arts and crafts) which may be interested in displaying such items (and/or its citizens who make them). Even if they don't have a current exhibit thay may want them for a display later, or may even get inspired to make an exhibit just for them.
3) Contact local stores (Bridal shops, knitting/crochet, sewing, crafts) which may be willing to display the items for awhile.
4) Contact the local craft/artisans guild. They may be able to provide a list of festivals, galleries and other places that would be interested in displaying such work (temporarily or permanently). They might also provide advice on insuring the items, should they be lost or damaged while on display somewhere.