I got to experiment a bit further with my remote and the openhab server, and I'm impressed with what I got so far.
It was a bit of searching and getting into details setting up the IR receiver part, but using Sam's help and code, it all came together. Once the openhab server can receive commands, it's all a matter of 'programming' the right actions to follow. The openhab system is very powerful, and allows much more than simply executing commands based on received codes. In the future, I might see what else I'll build into the system. (There's e.g. easy presence detection possible based on whether or not your smartphone is in the neighborhood, which could also trigger stuff to happen in your house.)
I currently have my BeoRemote One control both itunes and kodi on an older mac. I even have the state of the system relayed back to the arduino, so the leds on the B&O IR eye are showing an active source, or blinking when signals are received.
My music sources map to different playlists on itunes, and the kodi app is present as a TV source. I have a playstation too, which could also be mapped as a TV source. It all integrates nicely into the BeoRemote, with the right names and the right options.
So far, I'm still using my old receiver/amp, which is too old to control with anything else than its own IR remote. The same holds for my TV. So I'm still bound to their remotes, but I'll have them upgraded later this year I guess.
I did get rid of my itunes remote app on the iphone. The BeoRemote nicely controls tracks, playlists, and volume of both the main zone and the airplay speakers separately. If my beolit 12 is plugged into the mains, I can even power it up using the 'oldskool' beo4IR function of the BeoRemote.
I'm happy with what I've got so far, and will be even more pleased once I get rid of the old equipment. The Holy Grail of one stylish remote to 'control them all' is finally here!