Hmm, I am guessing that the problem here is just Pierogi's user interface? (I think Pierogi should already be able to work with most Sony TVs and audio systems, and can emulate several of the remotes listed on the Eventghost website. It should already be able to control all your devices...)

Unfortunately, the guiding principle I've been trying to follow with Pierogi (for better or worse) is to keep the UI, as much as possible, independent from any actual remote control hardware. This serves the purpose of styling Pierogi as a single "universal" remote (where all the buttons are always in the same place no matter what device you are controlling), as well as letting me attempt to optimize button layouts for the N900's screen.

There is, at the moment, no way for an end-user to create a customized layout. I was starting to create a set of user-defined buttons a while back, but those are still stuck with the problems I've been having in creating a macro system...

Would it be possible for you to create some Eventghost scripts tailored to Pierogi instead? You wouldn't even need to use the Sony keysets, it looks like Eventghost can handle almost any keyset. Pick a keyset you like (maybe something like an LG or a Samsung one that has a lot of available controls), make it a favorite keyset (along with favorite keysets that work for your Sony TV and audio system), and you should be able to control all three devices fairly easily from within the Pierogi system...