Is it possible to use a computer as a rack module? Like, say, plug it into a controller keyboard for live performance?
Use RAX on a Mac, works very well and cost about 30$.You can load any VI or FX in AU or VST formats.You can easily build different set-ups for each song in a live situation; the CPU load is very small.
On PC I've heard that VST Stack works also well but don't have a personal experience on this.Check also Plogue Bidule.
And when it will work (lots of bugs until now) Native instrument Kore is really good about organising sounds etc........