There is!.. if you’re willing to poke around in your user_settings.json. [This is in your Stonehearth folder; for me it’s C:\Program Files (x86)\Steam\SteamApps\Common\Stonehearth.] It’s really just a plaintext file, so even Notepad would work.
So after the last option you have, you’ll want to add a comma, press enter, and type "infinite inventory" : true.