Hi i know this isn't exactly what you wanted but this is a little touch i use in my workbooks when there processing a function.

I set the status bar to my own custom processing comment.

You can also do the same with the MS Excel caption heres a bit of code to show you how to do it

Dim status As String
Dim caption As String

status = Application.StatusBar
caption = Application.caption

Application.StatusBar = "Processing..."
Application.caption = "Processing..."

'Start Function


'End Function
Application.StatusBar = status
Application.caption = caption

Hope This Helps