I can’t declare I will help writing it at this moment because I have never dealt with Blender’s Python API, either 2.4 or 2.5. I started digging into it, though, so as soon as I get the hang of it I would definitely like to help.
Additionally, this initial work by Hypnos has been laying around for a while now => [minimalistic exporter for blender 2.5). I don’t know how good or bad it is – it sure is very basic, but can’t judge the quality of this basic stuff – but I thought a link to it should be here, so if anyone decides to dig into this matter right away, they can at least take a peak into it.