This contest starts on Patternreview on July 15th and runs through August 14th. It's one of my favorites, and a contest I would absolutely enter if I could (Contest Committee members can't enter contests, for obvious reasons, although I did get special dispensation for the Menswear Contest last year).
This contest always starts a lot of discussion on the boards about what can and can't be done and what changes can be made, but sometimes I think people just overthink it. Sometimes you don't need to do anything drastic to a pattern to turn it into a completely different dress - sometimes all it takes is fabric, or a different neckline, or even a different attitude.
One of my favorite patterns to do this with is Burdastyle's Fatina dress. I've made this pattern three times now, and none of the dresses resemble each other in the slightest, and I made no major structural changes to the pattern for any of them.
The first, the black and white pinstripe, wasn't altered at all, I just added the amazing floral trim.
For the second version, the plaid, I separated the bodice from the skirt so that I could cut the bodice on the bias and added a ribbon over the seam. I did add a short sleeve, but I don't consider that a major change either.
The third version is the most recent, and for the chocolate swirl dress, I kept the separate bodice and I sliced the skirt into thirds and added a hem band.
Three distinctly different dresses from a very simple pattern, and a very roundabout way of saying I made another dress yesterday, from another summer TNT (BWOF 2/08 #113), and all three iterations of that dress will appear shortly.
I'll try to get a picture of me in the new dress tomorrow if I wear it to work.