ok while… i poked around a bit, reducing += string operations given those mechanisms http://wiki.python.org/moin/PythonSpeed/PerformanceTips#String_Concatenation
it reduced the export time from 200 to 180 seconds.
appears that the tangent and binormal generation take the lion share and i cant find any 2.59 references for tangent calculation code. altho blender sure is capable on c level as it. so… until blender wraps up the tanget calc , disregard my performance advice above. btw. respect for caculating tangets and binormal manually.
i would favor a switch to turn tangets and binormal calculation off. Unless one uses normal maps those may not be necessary.