[plt-scheme] whole-module compiler extensions

I'd like to perform static analysis on Scheme programs that isn't local to
a single invocation, i.e., can't be done with a macro. I'm fine with
closing the world at the module level, but I need to be able to analyze
the entire module.

What would be the best way to go about doing this? I'm happy to hack the
PLT sources but I'm not sure where to look. I've started looking at the
PLT extension tool library, such as the Algol60 collection, but this is
too low level: I'm looking to add a static analysis on top of the existing
Scheme language, so it should use the same reader, parser, module system,
library, etc.

Thanks (again)!

Dave