Early Mac Clones

I'm reading _Build Your Own Macintosh and Save a Bundle_ and it has an interesting reference to early Mac clones. The book states: "The same Apple Macintosh Powerbooks that legitimized the whole Macintosh portable area have spelled the death knell for most other third-party Macintosh portable builders who cannot compete with Apple's overwhelming manufacturing economies of scale. While Outbound continues to flourish-thanks to a wisely forged legal agreement and clever positioning of their Macintosh portable models versus the Apple Powerbooks-I question their long-term staying power. Most other third-party Macintosh portable vendors have either gone out of business entirely or have quietly dropped their portable offerings." Does anybody know anything about these "thrid-party Macintoshes?" I'm familiar with the Outbound computers, I have never even heard of any other early Mac clones. Any info? Thanks, Tom Owad