There's many alternatives, but they lack much. There's always Virtuozzo, though it costs quite a bit more. We're all seeing a possible void to fill here. I don't mean to be insensitive(I spoke with Kt quite a few times in the past) but there is an opportunity here for someone to step up and fill his shoes.

That being said, it will no doubt take far more than 1 man to do what he did. http://www.vtonf.com/ looks promising..