It's very possible to complete it in less than a month, you just have to be dedicated and be willing to commit a lot of time to it. Don't get distracted by forums, web browsing, video games, etc. Set some mini-deadlines to make sure you're on schedule. It'll also help to have friends there to work with you and keep your sanity. Pepping by yourself gets boring fast and its easy to get distracted.
I "finished" and ODST suit in less than two weeks. I just took a lot of shortcuts to reduce the amount of pep. That's a little harder with the MJOLNIR-style suits, but it's something to keep in mind.
Also remember, if you have to cut down on the polishing and detail, at least make sure you get a good paint job. A good paint job will do wonders for covering up little flaws and defects.