Boeing's website suggests about 10 777s have been cancelled in recent years. Combine this with a few deferrals and you could squeeze in a few extra.
One suggests that with the recent fuel price rises, some carriers would be happy to defer (not cancel) any deliveries which are purely for capacity increase (as opposed to replacing another, more fuel-guzzling type) until the dust settles. Similarly, these boards were very recently awash with stories of some carriers parking aircraft due lack of crews - if that's still the case, then they would be deferral candidates until that situation gets sorted out. A carrier with 15/20/25/30 777s already in service might be happy to put 5 or so they have on order, back from 2012/3 delivery to 2014/5. And manufacturers would bend over backwards to 'defer' rather than 'cancel' as canx'es look bad for their stats; a deferral (or slot trade) allows them to then put a positive spin on it when a 'new' order is forthcoming (especially from a new operator of the type).
Don't forget also that some slots are held by lessors 'on spec' - that is, ordered by the lessor before they have placed the aircraft with a carrier. Hence a three-way could be done between Boeing, the lessor and the carrier (eg. lessor places frame with carrier and Boeing covers at least part of the lease cost as part of the compensation package).
And it would not take much to ramp-up from 6.5 per month to 8 or so. Lack of orders on the 767 line (whilst using different tooling) would at least free up some labour and floor space for a slight increase in 777 production.
404 Titan - I seem to recall from my visit to the Everett floor that 767 and 777 production is on the same line (but that was 5 years ago).
I suspect the 'discipline' that Boeing is talking about, is resisting ramping up from 6.5 to 10 or so. Recall 10-15 years ago when 747-400 production was ramped up to double figures, there were all sorts of quality control issues; then industrial problems when Boeing sought to lay off workers as things slowed down. Then they got really scarred by a month-long strike a few years ago. I suspect they are keen to avoid that sort of cost (both monetarily and to reputation) again and so would rather see a few orders go east rather than make promises they cannot ultimately deliver upon.