I want A1 to equal the contents of a cell in the "last row with contents".
If not, then I want the cell in the row above it, and if not I want the cell
in the row above that, and so on...

For instance...

A1=5
if...
D1 is 1
D2 is 2
D3 is 3
D4 is 4
D5 is 5
D6 is (empty)
D7 is (empty)
....

Second Example...

A1=4
if..
D1 is 1
D2 is 2
D3 is 3
D4 is 4
D5 is (empty)
D6 is (empty)
D7 is (empty)