It's odd that he "can't" get you the parts to swap it out. He can get 'em from any supplier from which he'd get mountain parts (presuming you're not looking at Dura Ace). This leads me to believe he just doesn't want to have the extra double parts sitting around as they don't fit with the plan to go solely with MTBs. Couple that with the lack of familiarity with road bike maintenance/support brought on by dropping them, and I'd look elsewhere.