If you use Debian or Ubuntu, or can set it up in a virtual machine, using Scratchbox (Harmattan Platform SDK) is your best bet for packaging. That way you can use the standard Debian packaging utilities and include as much or as little as you want in the final result. There's more than a little bit of a learning curve, especially if you haven't worked on Debian packages before, but because of that you also learn a lot about how the package system works.