I have project to build Groupon Clone site. I have researched number of clone script such as NDOT, [url removed, login to view] and groupclone.net.
[url removed, login to view] is looks nice and it is build over Magento which might be stable and easy to customize compare custom scripts.
There are few other Magento extension for Groupon Clone.
If you have better idea and experience please bid. Your bid have to be only script setup and licence fee.
We will talk other issue such as design and customization.
one things I should mention that We need mobile App's for iPhone.