peter dmz wrote...
....
>That is, what I would like is essentially "=sumproduct(A1:Z1,Z2:A2)"
>but of course that won't work, as excel always takes the range from left to
>right.
....

With some hardcoding (the '26'),

=SUMPRODUCT(A1:Z1,N(OFFSET(A2:Z2,0,26-COLUMN(A2:Z2),1,1)))