Well, the results of my next-to-non-existent decorating skills at least. There are 8 overlays with different amounts of moss. I used Kativip's ivy along with my recolors to show what can be done. No cheats were needed to place any of the overlays or the ivy. (I did cheat to place other things, lol.)
There are 2 downloads available through this post:
1) The recolors. This also includes an EDIT of pixelhate's mesh. I made it a bit wider as it didn't truly cover a full wall tile. (Which made these recolors look a bit strange since they ended a bit short of the edge.) His original mesh isn't set up for transparency- which means any transparent recolors have to have their TXMT edited. So I changed that too. You can still do opaque recolors- this change just makes it 100% easier to do transparencies. If you would like my edit just replace the original 1-tile mesh with mine.
2) In the screenshots you might notice the windows. Those lovely windows are by leesester and can be gotten at Mod The Sims. What's IN the window is what's in the other download. Those lovely green things are recolors of a Sims2Cri sticker mesh by Lama at The Medieval Smithy. The original mesh needed to be placed in the window using cheats. It also couldn't be seen on the other side. I edited the mesh so it sits right in the middle of the wall. I also added a reverse side so it can be seen on both sides of the window. It still lets light in through the windows- and works rather well with a lot of different windows. If you want my edit just replace the original Sims2Cri wallsticker mesh with mine. (There are a lot of wall sticker meshes available so I didn't feel this change would be taking too much away.) No cheats are needed to place the sticker in the wall. Picking another color IS a bit trickier: there's a tiny bit of the mesh that sticks up above the wall. If you can click on that, alright. If not- try clicking on the wall above the window. (That's the way I do it!) If you're having trouble, try the other side of the wall. I've done window film before and can guarantee you that once you get the hang of it, choosing another color is easy-peasy. :)
There are 2 that are rather full, 3 that are spotty and 3 that are rather bare in the middle. Those 3 are meant to go around windows. They won't work will ALL windows- you can see the moss with taller windows. I rather like that look though. All of the recolors can be layered for different looks. So with these 8 recolors you should be able to get a lot of variety. They work best with brick or stone walls for 1 reason: they will also make a wall look a bit eroded. Old, mossy walls wouldn't look perfectly new so I added a bit of embossing that I think gives walls an older look and feel.
Chatty MLC is chatty this morning!! I just want to be sure that I don't leave anything out. If you have any questions, ask away!
Edited Overlay Mesh & Recolors
Edited Sims2Cri Wallsticker Mesh