[M]ap [a]nd tatic eeker or MaSS
Created by : Eri from uo-pixel.de
MaSS allow you to save a portion of a UO map to file or you can use the tool to insert map data from a saved file. The tool handles both Static and terrain data. However the tool has a little downside is that is all in german, so google translation will be needed until you get the hang of it.
I've experimented with MaSS a short while and it has serious promise. It can allow you to save previous work for future map project as well as collect resources from old maps that have been abandoned. This tool can certainly help cut the build time on large maps and assist in rapid prototyping but dropping all the elements for a town for example.