I don't think so. I'm pretty sure it's possible, using mod_perl, in versions less than 2.0. Although you may be right that the support for *module* chaining (as opposed to stacked Perl handlers) comes with 2.0.

There's a module called Apache::OutputChain, and there's another called Apache::Filter. Both do sort of the same thing: they let you chain together several modules, with each successive module being able to write to/affect STDOUT.

The OP should probably take a look at these modules. In particular, Apache::Filter might work for him, in combination with Apache::SSI. Something like this in httpd.conf:

    PerlModule Apache::Filter;
      
    <Files /foo>
        SetHandler perl-script
        PerlSetVar Filter On
        PerlHandler YourModule Apache::SSI
    </Files>
[download]

In YourModule, just print to STDOUT (or $r->print, I suppose). This output will be filtered through Apache::SSI, which (I believe) should fill in the includes.

Mind you, I've never done this myself.