After doing some more experiments and work with attributes, there are now two more modules on CPAN: Attribute::Util, which provides four general-purpose attributes (Memoize, Abstract, Alias, SigHandler) and Attribute::Overload, which allows you to declare a subroutine to be an overload handler for one or more operations.
I've also submitted a proposal for a talk on attributes to YAPC::Europe (yes, I know the CFP deadline is today...)
Work still continues on Exporter::Simple, another module that uses - surprise! - attributes to make life easier if you want to export variables and subroutines. Damian is about to release a new version of Attribute::Handlers and so I'm delaying the release of Exporter::Simple; there are still a few things to be implemented.
I've quit my job (it was the end of a project) to spend all summer hacking Perl (ok, I'll try to get out every now and then...), and you just get so much more done if you can work a) on what you really love to do, b) in concentration, c) without commercial pressures.
I'll start looking for another job in September, but again it'll only be to fund some more time on what's really important.