I've been working on this matrix and world editor, at first just for my own use. Then I got carried away. Its called Worldmaker. It's still very new. The interface is clunky. There are some things not there that could be there.
You can use it to build a matrix - up to 100x100. You can texture it with up to 16 textures. There are some interesting terrain tools that can be used in combination to generate almost any kind of landscape. You can also set individual points and tiles.
You can load x or dbo objects, yrotate them, scale them, texture them and place them. There are some basic objects included - wall segments, columns, etc. They are presized and rotated, so you can use them if you like and you get static collision boxes.
You can save and load worlds. There's a subroutine included to load the world in your game. Its very clear and simple, so you can change it easily. There is also an example.dba
Its mostly point and click. The manual is limited. You can email me any questions, if you like. Any complaints, advice or accolades are welcome.
The folder is zipped inside a 7zip self extracting archive, about 2.7 Mb download. If you have any problems downloading, please let me know. Oh yeah, it's here:
http://awfuldarkforest.tripod.com/worldmaker.html