Rotor makes really short crank arms - all the way down to 150 or 155, if I remember correctly. And you can put Rotor arms on SRMs - pricey I know, but I've seen used ones going for $800. (In fact, there is a 170 Rotor SRM on Online Swap Meet this morning.)

I also saw a DA 165 SRM on either Slowtwitch recently.

You can also get a Quarq in those sizes, and if you don't like the arms, just swap them out for longer ones.