notional subject-verb agreement other than for measurement, degree, etc
There are three often conflicting 'rules' that operate when one is deciding what verb agreement to use in less obvious cases: the traditional simplistic 'obvious/surface' rule, often called disingenuously 'grammatical agreement' (as if the other two weren't); proximity agreement (more than one boy is here); and notional / logical agreement. There is ample scope for people to disagree on which one should prevail in individual cases.
I doubt that many people would object to the proximal pull of 'a lot' in
Six to seven children is a lot.
– though I'd say the underlying factor is the notion of a large (and demanding) family group. The notional agreement of '1,000,000 dollars is a lot of money' is surely the only acceptable version nowadays, even though dollars are of course etically countable; where it makes sense, discrete measures are often treated as if they were continuous (and thus as mass concepts). Confetti (though etically count) is treated as mass, and I have no problem with using similar notional agreement for
7 children is too many to raise together.
as short for the idea 'trying to raise 7 children together – that's too many'. In fact, I'd prefer it to plural agreement (you're addressing the situation, a 7-child family, rather than Ali, Ben, Charlotte, Denzil ...). I don't think that there are many anglophones who would object to
Bacon and eggs is my favourite breakfast.
(notionally, A meal of bacon and eggs is ...)