Hmm, if you're wanting solid drawings (ie: rendered output), then you can fake it using either a plugin (such as Eki's Fakemetric Camera), or you can do it directly in layout.
Set your camera at an extreme distance from the model, and simply zoom in the required amount. This will remove almost all perspective from the view. By moving the camera to the same distance on each axis, you can then obtain three images to stitch together for an orthographic projection.
Failing that, you can always simply screengrab from Modeller
