NEMA 17/23/24 STEPPER - ALL PARTS?

Hi

Does anyone know of a model on here, or anywhere, of a fully modelled stepper, or at least the 'crucial' parts? I'd like to have a go at building my own, but keeping within the NEMA frame configuration. I've looked around a lot, but can only find 'space' models.

Love the site btw :)

Thanks

UPDATE: Had a rethink, there's loads of alternative info out there, I can make it up. If anyone does know, though..?