Parrot is today very powerfull <sic> and even in the first versions, it can already be used to a lot of stuff. But it still have a long way for hosting a full Perl 6.
I may be wrong here, but isn't the issue with hosting a "full Perl 6" the fact that Perl 6 isn't finished? From my understanding, both Parrot and Pugs are implementation of what currently exists of the language, and are used for testing, not as what "perl6" will be. So the Perl 6 development isn't centred around those two projects, and a third one won't help Perl 6 to be released any sooner.
Software speaks in tongues of man; I debug, therefore I code.