I faced the same problem lately. My solution was to patch ppm so it doesn't delete the temporary files it creates. This can be done by simply commenting out the lines

247: rmtree($tmpdir) if $tmpdir;
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and

309: unlink $filename;
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After patching and installing the modules you need, you will find the downloaded tarball somewhere in your temp directory. This doesn't save the .ppd file, but creating a ppd for a tarball you already have is trivial.