BevvyB, though there isn't a way to create tick box lists directly in OF, you might be interested in jharrison's
Project Folder and Project Notes scripts. The scripts create project folders and project notes as OmniOutliner files. You can, of course, manually create an .oo3 checklist and attach it to a task's notes field, but the script automates it a bit. druido has recently posted updated versions of both scripts in
this thread.