There are also quite a few native plants which are somewhat similar

Do you have any specific thoughts. This is part of a drainage
solution. Gutters already drain at least 10' away from house, under
the deck. Am regrading this area so that all water flows into French
drain under front edge of deck which then moves to the side and down
the lot into a lake.

So the plant is for the "down the lot" area, and you want a plant
which likes wet soil? Before I get to that, there's the issue of
preventing the water flow from washing out that whole area (especially
while the plants get established). Don't know if that's going to be a
big issue for your setup, but if it is there is the bio-log (coconut
fiber wrapped in rope). You put them cross-wise to the slope, and
they should give the plants plenty of time to establish.

I'm sort of assuming you want something low to the ground like the
Mondo you mention. If something taller (cattails, New York ironweed,
etc) would be appealing, you have lots more choices. Or even
short-ish but non-grass-like plants.

The Blue-Eyed Grass I mentioned is Sisyrinchium angustifolium (the web
site below says dry to moist soils, and sun to part shade). There's
also a taller Sisyrinchium atlanticum which is moist to wet soils and
full sun.

As for grasses and sedges, I don't know those very well (yet), but a
few short ones a
Carex pensylvanica (part to full shade, dry to moist)
Carex glaucodea, blue wood sedge (part to full shade, dry to moist)

I'm browsing these at http://www.nps.gov/plants/pubs/chesapeake/ so if
you go there you'll know almost as much as I do.

As for where to buy native plants in Virginia, a couple worth
mentioning are http://www.nature-by-design.com/index2.html (DC area)
and http://www.hylabrookfarm.com/ (a bit closer to you, although not
really). Some of these plants might be in some of the more
conventional garden centers too, but I don't know Virginia Beach that
way. Many will ship by mail.

I'm not sure if this helps. I don't know what your voles would eat
(and trial and error might be needed on that one).