I would check ebay and possibly ask at the Leica forum on photo.net if someone there is willing to sell. I would suggest "stepping up to a IIIc" While similar it has the windows closer together and I believe the top plate is one piece. There shouldn't be a price difference of more than $50. I would guess you could pick up a IIIc (or b) with an 50mm Elmar for about $300-350 or so maybe a little bit more depending on condition.