Tambien lo podes hacer con elapi MoveWindow .
Private 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
Private Sub Form_Load()
For i = 1 To 1000
Combo1.AddItem i
Next
Me.ScaleMode = 3
MoveWindow Combo1.hwnd, Combo1.Left, Combo1.Top, Combo1.Width, 500, 1
End Sub