I bet a large percentage of Asians are not international students. Top O&D market from BOS to asia includes NRT 67000, PVG 44000, ICN 43000, PEK 39000, HKG 39000, BOM 31000 (all per year for 2010 ending in Q2). CX has a good shot at attracting HKG, BOM passengers and those going to South East Asia, Southern China, Taiwan. So if you add up, they could fill a 787 3-4 times a week, but I am not sure about the yields.
While I agree you definitely have the # of bodies for that amount of service, my suspicion is the biggest problem with 3-4 weekly service is you significantly dent premium demand, which is needed to make that load profitable. Problem is business travelers demand frequency....so you'd still probably have the situation of the premium BOS travelers connecting via YYZ, JFK or ORD. The meeting in HK isn't going to wait because your BOS-HKG flight doesn't go today and tomorrow.
I reckon CX could easily fill a plane 3-4x weekly to Seattle, Honolulu, Boston, Philly, and maybe other cities....but the problem (in my view) is making the load a profitable one, especially given the existing frequencies (2x daily SFO, 3x LAX, 1x ORD, 4x JFK, 2x YYZ, 2x YVR) are numerous. If the rumor about EWR is true then you'll have 5x dailies to NYC! There is a clear pattern in what CX does for North American routes - emphasize frequency over # of destinations. I bet you see either SFO or ORD get another daily before you see a route like BOS. And alas, even if there is a new route, I'd have to imagine DFW plays into the cards first.