It could be a Graptoveria hybrid, the flowers match those on the first link, and there are some which have leaves that look the same shape. Unless you can match the leaf shape to a plant with flowers the same it's impossible to say anything for sure and even if you can it's not certain, there must be a lot of hybrids.
http://www.lapshin.org/succule...
http://www.smgrowers.com/produ...
