You can find some more information by searching previous posts about "what grows under a maple tree"; Groundcover and Shade forums--you might find someone who's had direct experience with specific groundcovers under maples.

I doubt the grass thing will work. The creeping forms of liriope might work, though I haven't tried it. I was able to grow Vinca minor, but with spotty coverage. If you lower your expectations about a "clean" look, you may be more successful, as the problem with growing under maples is that you can't ensure uniform conditions that address soil, water, root competition, so you'll have pockets of success and failure, compared to photos you see of those great southern gardens with the liriope under oaks. The wild violets will pop up everywhere (not necessarily a bad thing)But maybe the creeping liriope will creep successfully. It is very invasive and may spread where you don't want it, but where it's happier.

If it grows in your area, sweet woodruff has done very well under my maple. It is also very pretty in the spring!