I found, downloaded and installed APT — Aperture Photometry Tool — from http://www.aperturephotometry.org/aptool/ today. It looks very promising! Because it is wrotten in Java it runs (well, walks sedately) everywhere. The same can be said of AstroImageJ for that matter.
Next plans are to evaluate it thoroughly and if it passes muster, write a Perl script to convert its output into BAA-VSS and/or AAVSO format.