there is a very nice detailed model, and in the thread he has views of every angle of it... but they arent blueprints, they are just screen shots of his model... do a search its easy to find.
as far as i know, there isnt any "Blueprints" of the pelican... you could do what i like to do if i need something, put halo 3 in take some nice screenshots and make your own blueprints... i like to use Photoshop, they turn out good enough for what i need them for.
also our good sir Spartan II is now in the business of drawing up very nice detailed blueprints, he charges but the price is worth the quality.