Universal Remote Control For Custom Application

Hi, I am looking for a universal remote control to control a custom application we had built for our public house. Its a karaoke application and I want to control it from my Samsung Galaxy phone. I have tried remote desktop applications but I find them very cumbersome to use. Ideally I would like a screen with 5 or 6 big buttons for the main control. Does anybody know of a universal remote control app that could be configured with a custom remote this way? (it also needs to control master volume). Or would this need to be a custom build solution?
Thanks

 

Great! Vectir looks promising - I will try it out now.

Thanks for the very quick reply!