The problem with ceramic is that the minimum bounding box has to be 40mm x 40mm x 10mm which is more or less the double size. If you want I can try to upload a bigger model and see if shapeways accepts it for their ceramic material? But you have to consider that it will be more expensive too.
I just measured the the prototype I ordered and the exact length of *one* of the lizards from tail to mouth is 24 mm which is about one inch.
Here on shapeway site it says a bit different, but I think they measure differently?!