Formula/Conditional formatting to determine Percent or Currency style?

I hypothetically have a dropdown in A1 that gives options of "Percent" or "Currency".

Is there a way to, in conditional formatting or by using a formula, determine the format of a cells style in A2?

The link describes returning information about a foreign cell as a value. What I need to know is how to format cell B1 based on the value of A1 (be it % // $ as general style or "Percent" // "Dollar Amount" as text).

The problem that I face is that any formula that I type into cell B1 to retrieve information about cell A1 will be overwritten once a value is placed into it. I was thinking that this won't be possible; but in excel it seems that this shouldn't be the first time a situation simliar to this has come about and there has to be some kind of workaround!

My first thought went to conditional formatting... however it falls short of my requirements. CF simply changes the font/border/pattern of a cell. It will not change the 'style'.

Anyone have any maneuvers I can implement?

I have been trying to do the exact same thing for about 2 years now and despite extensive searching haven't yet managed to find an answer. It would seem that you should be able to use custom formatting to complete this but it doesn't appear to allow you to reference an external cell only static info e.g. "custom text"#,##.

Has anyone managed to resolve this? I would *LOVE* to know the answer!!