As Marco Ceppi has pointed me towards launchpadlib, I wrote a little script that will do this for you.  download it here

Run the script by calling python name_of_the_script.py in a Terminal after you've downloaded and saved it. It will ask you for a programming language, case insensitive, and a search query (where wildcards, *, are allowed). If you leave either of them blank, it will search across all, rather than none.

You'll need to install python-launchpadlib before you can use it.

Here's some example output:

stefano@3000-G530:~$ python test.py 
Enter a programming language or leave blank to find projects in all languages:
>>> Python
Enter a search query or leave blank for all:
>>> Calculator
calcool - A document based calculator tool...
evias - Web site used to apply Eve DB dump to Eve API results and get th...
txevolver - txEvolver is a Twisted-based set of libraries for performing ...
[...]

Illumination Software Creator

This is a proprietary commercial application that costs $39.85 US (available from Ubuntu Software Centre) and seems to be offering what you are looking for. As far as I can tell, it is a GUI where you set out a flow chart of user interactions.

I would recommend you try quickly. It allows you to easily create applications. It generates a project template containing much of the required boilerplate code that you can then edit. It allows you to design the user interface in Glade, a graphical designer.

Quickly also handles packaging and uploading to PPAs.