@ Zohan, edizzle:

Don't get me wrong, I'm not cheap. I'd love to hire a pro to do this, but I can't find anyone around here. I'm living in Vienna, Austria and I'll even have to get the multizone amp from the US because all we have is either Sonos, or systems that start at 3000€ for the amp only. I've been to 6 places and told them what I wanted (basic functions using IR with small CC remotes, Media selection via apps, no keypads). They told me quite bluntly that I was an idiot and really what I wanted was this Sonos system. One of them even agreed with me, that my solution would be more convenient, but said it couldn't be done.

If you happen to know someone in Austria who can do this (Germany or Switzerland would probably be close enough even), do tell me. Otherwise, I'll have to give it a go myself with the help of some DIY and tech-savvy friends, trainwreck or not. It already pretty much works if you use the keypads as IR routers. Going to look into that Xantech solution, which would replace the Myrobridge AND the keypads, but if it's too much of a hassle, I'll just pay up.