I implemented the new strings which start off as strings of octets and upgrade transparently to 24-bit strings capable of representing all Unicode 5.0 code points. Dan's Unicode library is almost finished, too.
Many languages shun integration with operating systems and existing standards such as Unicode, HTTP, XML, and so on, because these standards are "dirty" and are beneath them. I think this philosophy is bullshit; it is just an attempt to pass off incompetence as elitism.
Factor is all about "embracing and extending" existing standards: we inter-operate with your existing software but allow you to build something better on top.