I've got a spare transmission with bellhousing, torque converter, and spacer plate. I've got a local guy asking to buy it from me for his ranger pickup v8 conversion project. Anyone know what a fair asking price would be, I have no clue of what to ask for it.
An economist would tell you that its worth whatever a buyer will pay for it.
As a practical matter, I'd check some local listings, or maybe eBay, and see what a similar set of parts for a Mustang C4 trans is going for. Then I would add 10-20% for the exclusivity of the smaller-sized MII parts.