I catched this tweet today. Apparently there is this 400i in the Haynes Museum in the UK. Typical this shows up since I added a few musea last week on this blog. I also included a musea tag and an entry on the sidebar (blog labels). So you can easily find where they are stored.
Their website: http://www.haynesmotormuseum.com/
#Ferrari#400i @HaynesMuseum pic.twitter.com/cRxw8nJsSp
— mikepbeausang (@lessismoremike) 29 november 2014
Update 10-8-2015: And another picture found with serial nr: Ferrari 400i # 43803
Update 21-9-2015: and another picture found