A simple imagemap with black horizontal lines on a z or x projection with repeat selected should do the trick.
For example a 1000px x 1000px white bitmap with a single black (choose your colour) pixel line at 100 pixel intervals scaled in the image map node to 1000 x 1000 (the scale is in meters) and set to repeat on the x or z axis will produce contour lines at 100m intervals.
Richard
oops yeah I too should read the section heading first, yes what Oshyan says

lol