Using the base model from the Mech Commander 2 game, I've converted a number of Battlemechs for use in map-scale Battletech games. The pdo files for each 'mech are set to print at 1:1000, or the same scale as standard Battletech maps. These can, however, be easily rescaled to suit your needs. For terrain and buildings in the same scale, see my Terrain and Scenery section, under Hex Terrain. There are currently around 30 models to convert, a handful of which are now complete.
Comparison of the 1:1000 figure compared to the Catalyst miniature (1:270):