first off, great thanks for writing the exporter 
it allows me to finally work with 2.5.
one thing i noticed tho. in the eggwriter. you use a lot of string operations that end up as… pretty big strings in the end. while this works ok for smaller models, it totaly breaks the export of big ones. trying toexporting a 70k mesh object… well i killed blender after it froze up for more than 20 minutes.
working with not so epic-long strings and writing them out to disk is a lot faster.