FoW often uses Rough Terrain as conceilment and in other ways. So why not doing them either yourself or let them build for you.
These ones are build and scaled for 15mm but also can be used for 28mm (e.g. Bolt Action, Napoleonics, etc... even Warmachine/Hordes)....
If someone is interested in buying these sets from me I will sell them for 5 Euros per set plus postage. Of course they will be delivered flocked and painted: