Hi,
I'm an experienced Flex developer and have published a few apps for tablets using Adobe AIR.
It's not clear if the collated APIs should be done in the app or on a server, but I suggest we do it on the server (I see PHP was listed, so that could be done). We can also think about pagination, "load more" and other improvements to speed up the responses.
I would have to see a snapshot of the app to better estimate the time needed, but I guess it will revolve around 14 days.
Please let me know if you are interested to work with me and I can go into more details.
Best,
George