The name is a cute anagram of "Perl six". There is an existing but dormant version, and a radically different to-be-released version.
So the Sprixel currently available at http://svn.pugscode.org/pugs/src/perl6/sprixel is an AST interpreter, but a fairly quick one when run on V8.
After several months of experimentation diakopter settled on C# as the new implementation language, to run on both the Mono and the .NET virtual machines. The new Sprixel will embed a utility called RunSharp to dynamically generate bytecode that gets JIT compiled to native machine code before being executed. It will also contain its own regex and grammar engine, and will probably have its own derived variant of STD.pm for the Perl 6 language definition. The microbenchmarks published in #perl6 so far promise extremely fast parsing and execution performance.