I don't think this could be done without VBA code, and there would be
restrictions even then. You would need the VBA code to create the text of
the footer in the _BeforePrint() event. Since any physical sheet can only
have one footer, if your sheet extended over multiple printed pages, the
footer would only be correct on one of those pages.
You're probably best off by simply adding rows where needed, whether for
each possible printed page or at the end of all printed pages for a sheet, to
provide the summary. Since you said you wanted a formula like SUM(A3:Ax), I
presume you only need one row at the end to provide your summary.
You might consider attacking the problem from the other end - that is,
putting your total at the TOP of first sheet (insert a new row 3?) with a
formula that included a range large enough to hold all entries in a column
for a long time, like
=SUM(A4:A10000)
??
