the new GED from conitech has one.
I think it is Beta now....
that is probably the best.

(alternatively)
you can also use MED to make terrain heighmaps.
Look into the terrain shader that comes with
gamestudio. i at one time used a paint program with it, and
got decent results.

if you do a google search, you can find others,
but to use multitexturing might require extra work....

I believe there is a plug-in for earth sculptor
that looked good,
but I don't know much about it.

-jimc74