You used to be able to get a Lo-max 3.0-1 for the np205 but i think i read somewhere that production had stopped and it's not on their web site anymore. I don't know what had happened but i was planning on getting one also. I'm sure someone one here will know what happened.
IIRC the lo-max setup was actually a new case with the gear reduction already installed and you just swapped over a few other things from your current 205 into it. But im pretty sure its not made anymore.
Yep, IIRC the lomax was the only option, and it required a completely new case and new gears, but reused internals like shift rails and shafts from your current 205.
If you have room for it, you could build a 203/205 doubler for half the price and a 4:1 reduction vs the 3:1 reduction of the Lomax.