Don't know of anyone doing anything like that except to flat fender the front and rear fenders.
Have you thought about just putting rubber/plastic fender flares like the CJ's and Wrangler's have to cover the hole or are you wanting it to look more stock. CJ8/scrambler, YJ, and Tj, rear flares are all close to the same shape as the stock Jeepster rear wheel well. Depending how big it is cut out will change which flare will fit the best.
If you search "fender flares" on this forum you will find lots of ideas and pictures of what fits. A few pictures were listed here of a couple flare options.
http://forums.off-road.com/jeepster-...er-flares.html (bushwacker flares)