CABrouwers, Looks like you already found a solution, but there is another way to go. I have used other solutions in the past (see below), but what I have settled on now is creating iOS programs from scratch (you can sign up on the Apple website as a developer) coupled with Global Cache's various products (e.g. IP->IR, IP->serial). That gives you a completely custom system that you have built from the ground up. Very satisfying!!
The device I used in the past (and that would have been ideal for you) was Philips Pronto Pro. I got very helpful advice on this website (particularly from members Lowpro and Lyndel McGee - always willing to help and very nice). I used the Philips for years and very much enjoyed programming it. My profile was very much like yours -- I wasn't trying to save money but I really just wanted to do it myself. Unfortunately, Philips stopped making the device (although you can still get them on eBay). As much as I enjoyed the Philips device, the iOS development environment is much better -- the Philips environment was somewhat klunky.