Searching around for alternatives (I must add... *low cost* alternatives) that feature both hits up an OSX native application, Cheetah 3D.
Initial tests seem to indicate this may be a really good low cost tool to combine with Unity; there are options for prebaking textures, a render engine, as well as the rigging and fbx export options I require. Note that I couldn't try export to Unity as I was using the trial version.
Controls wise, there are options for Maya or Mirai style controls, so no issues there. Interface is going to take a little while to get used to, but hey it's a new package.
Some may be curious why I'm not using Houdini, since Houdini supports all of what I need. The reason is cost. Houdini Escape is far beyond what I'd want to spend on for a fun side project. Requirements wise, what I need are modelling, hard surface rigging tools and fbx export. Using houdini for tasks like this is like purchasing a Ferrari for a trip down to the supermarket.
I think the procedural capabilities of SOPs will be really handy for generating procedural terrain, buildings, structures and stuff. Maybe one day, when I get serious.