I decided that I really didn't know enough about the topic, so I asked my friend Alex Stone to address the issue of a Linux-based composer using high-quality commercially-available sample libraries. I admit that I was surprised by his response, but as far as I can tell it's simply the plain unvarnished truth: If you need Kontakt-formatted sample libs you're just out of luck if you're working in Linux. Alex advised - unhappily advised, I must add - using a Windows box as a host for such libs, but that does not seem like an alternative for you. However, I recently perused a lengthy list of sample libraries for popular and other musics "not classical", and I was pleased by the number of vendors who provide plain WAV and/or AIFF files as a supported format. Not very helpful, I know, but it gets closer to the truth of the situation. I hope this reply clarifies it a little more.