It's not quite the blueprint I hoped for, but it will certainly be useful nonetheless. I'll print it out tomorrow morning to read over lunch.
Only having skimmed the article, the section on Zones & Jails caught my eye. I had noticed that zone implementation simply wrapped FreeBSD's jail interface when browsing the compatibility layer, but forgot about / disregarded it. I understand that there is no analog in NetBSD, but at this point I am unsure whether it is best to completely axe code, or if it's cleaner to null-stub the zones interface.
It will be better to discuss all of this after I read the article more fully.