So, new version of the script is up at
http://people.pwf.cam.ac.uk/~ajd70/mdl_export.py
Features this time are added are:
*Scale button now works.
*Added a flags parameter. At the moment this is just a number entry field, if people really need I could change it to a series of toggle buttons for each flag. There's no way to make check boxes in the standard package.
*Added UV fixing options. Translate UV's means that UV's outside the range are moved up/down by skinwidth or skinheight until they are in the range [0,skin(height or width) - 1]. This is useful if you find the uvs are aligned up with the skin, but in the range [-1,0].
Clamp UV's just moves any points which are out of range to the nearest edge of the skin, so if it's at -5 it gets moved to 0, if it's at skinwidth it gets moved to skinwidth - 1.
As a promo, I spent 30 mins converting one of those sweet TF2 low poly models to mdl format. The time consuming things were duplicating the polys that should be double-sided and making a conversion of the skin to the quake palette, once you use the blender "Consolidate onto one image" function the actual conversion is painless.

The Sniper