Looks great!
I really like the way the hill looks like a smooth curve. Very cool. I have built a few small similar ramps (none looked as nice as that one!) but have run into an interesting problem. Even though it's meant for inside, the odds of you just rolling up (and down) the other side turn out to be slim. Ramps are ment for jumping. Hills are meant for rolling over. I'll have to see if I can find a pic. (I don't have the ramp any more) but I had a way to extend the center. I wanted to still land on the ramp on the way down, but wanted a little air time before that landing.. and with a ramp like yours, I could never get myself to lay off the throttle and take it nice and slow.
Great job on the ramp. Can't wait to see the finished project!
Brian