Question about big end bearings for a bug engine

I have a query and hope than someone can help with my question. My name is Karin BTW and I'm wife of VOLX (Linus).We're having an engine rebuild at the moment and have been waiting for bearings for months now (10 mths actually)as the mechanic tells me they are not available in Australia. I finally asked exactly what size are we looking for and he said 1.25mm over size from original 1600 crank. I have since been told today that if crank has been machined over 1mm then the radius has nothing left to grind and the crank will actually crack. Does anyone know if this is the case? The engine is an 1840 and used to be very nice until the generator stand broke and broke the fan and the blades came through the fan housing and stuffed the engine. This mechanic is charging us top dollars to fix this and now I'm beginning to worry if this means the crank will soon stuff up, If anyone can offer some advice this would be great before this guy goes any further with this engine.
Thanks
Karin

Get another crank eg.nice original german crank with journals cut at .25mm,.50mm.Should cost almost nothin or get one of these http://www.cbperformance.com/catalog.asp?ProductID=1185 :thumb by the time it lands about $350AUD ps.10mths is 9mths too long to wait give the maestro the flick😉

Well I rang the mechanic this morning and apparently the crank is a performance crank he said it's a "counter weighted crank" and can be ground up to 1.5mm. Does this sound right or is he having me on?

Thanks for the link with the performance cranks, I'll look into this.