Ignoring blanks in a dynamic named range

I used each of the following codes for dynamic name ranges.

=OFFSET(INPUT!$L$4,0,0,SUMPRODUCT(--(Detailed!$L$4:$L$27<>"")),1)

=OFFSET(INPUT!$L$4,0,0,COUNTA(INPUT!$L:$L)-1,1)

And each one ignores blanks at the END of the list. I have a list that users can change the names in and delete names. I have a dropdown list that is validated based on this list, and it needs to ignore blanks IN THE MIDDLE of the list as well. So no matter what cells they clear or rearrange, the dropdown list will only contain any cells with a value in it and ignore all blanks. The list is in L4:L27 on the INPUT worksheet.

This is Excel 2007 and the worksheet and cell references at the top are accurate for my worksheet. Thanks!