Obrigado, meu caro
O djrobertosc postou uma solução em outro fórum, testei funcionou parcialmente, somente a cor branca. Estou buscando outras soluções ainda.
Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long) As Long
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hwnd As Long, ByVal crKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Long
Private Const GWL_STYLE = -16
Private Const WS_CAPTION = &HC00000
Private Const WS_SYSMENU = &H80000
Private Const WS_EX_LAYERED = &H80000
Private Const LWA_COLORKEY = &H1
Private Sub Form_Load()
' Altera a cor da barra de título para vermelho
SetWindowLong Me.hwnd, GWL_STYLE, GetWindowLong(Me.hwnd, GWL_STYLE) Or WS_CAPTION Or WS_SYSMENU
SetLayeredWindowAttributes Me.hwnd, RGB(255, 0, 0), 0, LWA_COLORKEY
End Sub