I've taken over maintenance of Sub::Uplevel. Two new versions have been released that address some stalled bugs.
0.10 -- fixes undefined value warnings under Perl 5.8.8
0.11_01 -- major change to the internals; now tracks uplevel calls using a stack, which fixes major breakage with nested uplevel and non-uplevel calls. I've also added a prototype to match that of the built-in caller function it replaces (which maybe should come back out given issues with prototypes).
The 0.11_01 release could use some field testing by those using Sub::Uplevel before I release it as 0.12.