vela

Oops, sorry, I read too quickly and thought you meant 140 t to LEO per launch, and three launches for the full mission. (I also had NASA's DRM 5 in my head, which requires three deliveries of roughly that size per mission, rather than Mars Direct which requires two.)

That's the super-heavy, which they have proposed as a competitor to a shuttle-derived (super-expensive) super-heavy.

The Falcon Heavy can throw ~ 53 t into a low-Earth orbit, and its list price is 80–125 M$ (http://www.spacex.com/falcon_heavy.php).

Terraforming is not necessary for settlement. It isn't even obvious to me that Martians will choose to do it down the line.

(I feel like I should be using terms like "minimum viable settlement" around here!)

International Traffic in Arms Regulations (ITAR, https://secure.wikimedia.org/wikipedia/en/wiki/ITAR).

Many space technologies are listed as munitions in the US, and revealing information about those technologies to foreigners counts as export. There are exceptions, and you can get export licenses (companies routinely do), but hiring non-Americans would be a pain—American employees wouldn't be able to share much information with them!

p.s. Under ITAR, all you need is a green card. I don't know if that's good enough for SpaceX—they might be under other restrictions than ITAR, too.