Graceful? Well, for want of a better robot-age adjective, yeah!

From: ROBOTS.NET
"Roller-Walker: A Leg-Wheel Hybrid Walking Robot"
"...The video shows a 2006 Japanese research robot called Roller-Walker, developed at the Hirose-Fukushima Robotics Lab. The robot has a hybrid locomotion system with legs that end in wheels. The wheels can be rotated so that the hubs face the ground and they act as feet for walking..."
http://robots.net/article/2334.html
Also...
From: SciFi.com
"Roller-Walker robot changes modes on the go" http://blog.scifi.com/tech/archives/2007/09/03/rollerwalker_ro_1.html>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Check Out: "CLASSROOM ROBOTICS" (the book)
http://www.infoagepub.com/products/content/978-1-59311-602-6.php