Well, Amiga expert I am not.. but electronics I do know and I overclock PCs... and I have to say I think your chances are about zero.
Unless you REALLY know what you are doing, in which case, it ought to be possible to:
Supply the processor with a faster timing signal to the rest of the system, probably with a daughterboard type setup, which plugs into the original location of the CPU. Overclocking the chipset is basically a no go as I understand it, because of the way the Amiga is designed in terms of synchronizing the video out, floppy access, etc.
John
edit: P.S. Just buy a cheap PC and get an emulator and/or AROS
