I notice that you provide a link to 3 older versions of Firefox Portable for use by folks using older equipment, and for diagnostics.
Considering there is a lot of interest in Portable T-bird 1.5.0.14, and almost no place to find it, how about some old version links here?
I love FileHippo's way of posting the very latest, and still making every past version available. PortableApps would get a lot more following if you did the same.