Thanks for the feedback!
I did what zookeeper suggested, and tried one in the store -- actually, several. It wasn't bad, and I was impressed with how the quality varies -- and that more expensive doesn't necessarily mean any better.
At Sears, they happened to have a Nordic Track model. It had all sorts of fancy electronics, but I doubted that I'd need those electronics to keep peddling away like a marionette.
I was ready to get one, but then realized something... I must put this device in the basement, which only has a 7' ceiling. I'm 6'2" tall, and the elliptical boosted me up in the air by about 12 to 15". Therefore, the elliptical is out for now -- Do'h!!!
SunniD -- thanks for the info about the knees. My mom is of the greatest concern, since she'd be "inheriting" this device from me, and has knee problems. I could already imagine what it looks like with laundry hanging off of it.
I'm back in the drawing board for a treadmill!