The ListCount Property may be the way to go. Here is a snippet of code using it.
Code:
Dim ListControl As Control
Set ListControl = Forms!Customers!CustomerList
With ListControl
If .ListCount < 8 Then
.ListRows = .ListCount
Else
.ListRows = 8
End If
End With
I think you can also set it up something like:
intVariable = Me.lstName.ListCount