Combobox- Itens apresentados

Em um Módulo

Public Declare Function MoveWindow Lib "user32" (ByVal hwnd As Long, ByVal x As Long, ByVal y As Long, ByVal nWidth  As Long, ByVal nHeight As Long, ByVal bRepaint As Long) As Long

Public Sub SetComboHeight(oComboBox As ComboBox, lNewHeight As Long)

        Dim  oldscalemode  As  Integer

        If  TypeOf  oComboBox.Parent  Is  Frame  Then  Exit  Sub

        oldscalemode  =  oComboBox.Parent.ScaleMode
        oComboBox.Parent.ScaleMode  =  vbPixels

        MoveWindow  oComboBox.hwnd,  oComboBox.Left,  _
        oComboBox.Top,  oComboBox.Width,  lNewHeight,  1

        oComboBox.Parent.ScaleMode  =  oldscalemode

End  Sub

Agora no form coloque isto

Private Sub  Form_Load()

        Dim  i  As  Integer

        For  i  =  1  To  15
                Combo1.AddItem  "Item  "  &  i
        Next

        Call  SetComboHeight(Combo1,  400)
End Sub

***  Onde 400 é o número que você aumenta ou diminui conforme o tanto de registro que quer mostrar quando abrir a combo.