[LAU] Any HW and SW based backing-band solutions?

Hi, This is a 2-part question: I'm playing in a little duo and we are using a Boss BR-80 which provides us with the backing-band duties on stage. The problem here is that it's only one output (Line/Phones - 22 ohms) that gives way to low output for line level, are someone aware of a decent pre amp (DIY is ok) that can be plugged into line input level in a mixer? The second question is about a backing-band software: In addition to the main output, it's nice when everybody can have his own mix (mono is ok). I'm not aware of a good SW based backing-band solution for Linux, are you? Right now, I can only think about something like playing a multi-track from the command line, IE. SOX (one track for each monitoring plus one or two for mixer input). Programs like Audacity and Ardour can't be used here, they take to long time to load and are also a gigantic overkill for this usage. The song need to be triggered (IE. with help from a script) from the space bar by a finger or foot, and the next song must be ready for playing when the current one is finished. I will not have any problem to fix the command line/script solution by myself. Any thoughts or solutions? Jostein