In addition to what HawkDawg says (and see thread 5774), you can use double walls and do not forget the possibility to use baseboards available in SH3D to have a different colour/texture on the lower part of the wall. Baseboards can be high. Later changes will be easier.
Also, using textures is a possibility. And often a better one. Easier to use with SH3D, but requires some work with a graphics editor (or the personalised texture guide approach).
In SF 3D Models 346 you will find some examples of textured walls. Your wall could be - fairly easily - composed with combining the tiles and the mosaic in a graphics editor. You create a graphics file looking like a part of the wall, full height. The image should not be too big (say 128x1024). When importing, set height = wall height. Eg like this:
+ 
becomes:
and will look like this: 
