Adding two transformers?
Two small turn count transformers would be smaller than a single
  transformer in the sizes I need


That's unlikely to be true for the following reason. The size of the transformer is largely dictated by the power it has to transmit through its windings and this, in turn, dictates the core size. Any ratio transformer is permitted provided there is enough room to cram-in the wires. Using two transformers to transmit (say) 1W of power means both have to be rated to pass this power and this means that they will together, occupy twice the volume of one transformer.

It's another matter if you can't get hold of a certain size transformer but there is always the option to rewind the secondary.

Here's a 100:1 step up transformer that is 6.6mm x 6.6mm: -



Do you need one smaller than this?