/u/ridddle asked for a filter to do a bulk replace of different block types at once without having to run Replace over and over again. (Requested at http://redd.it/1lbew6, and the final product here)
This is that filter.
Progress is printed out to the MCEdit console
Please note that the implementation uses a function that appears not to work in the Nether or other dimensions. You can edit your region by copying it out of DIM-1 (for instance) into the region directory to edit it.
MCEdit Filters >