Interestingly, I discovered that there is a robust after market for Miche Shells. Miche Bag of Salt Lake makes hand bags with interchangeable shells. This way you can match your shell to your wardrobe.
As people's wardrobes change, they will want to change shells, making for an interesting little after market. The online price for the shells seem to run from $25 to $50. Used shells seem to be going for $12 to $25 on ebay. Hmm, I would have done better investing in Miche Bag Shells than in the stock market.
It will be interesting to see if Miche creates a sustainable market, or if they oversaturate the market. Anyway, I will be keeping an eye out for used shells when I visit garage sales this summer.