Try the Robotic Vacuum by P3 International. $44.05 on Amazon.com [plus shipping]. I ordered one to check it out. We have a lot of low pile carpet and wood floors that Amy sweeps every day. Hopefully this thing will work and save her some work. I only found one review but it was generally positive.
http://www.amazon.com/dp/B000MT0M1G/?tag=tcg21-20
http://www.amazon.com/dp/B000MT0M1G/?tag=tcg21-20