Upgrade existing website using HTML 5

We need our current web app to be redesigned and upgraded using html 5 and related technologies. We need suggestion for time frame and a ballpark cost for this work. More details would be provided to experienced developers. You need to prove your ability to develop rich apps using html 5 and ajax. Please show live examples of related work on your private message. Mention "html 5 master" somewhere in your bid. All the best.