This happened on the bridge just before Franky used Funkfried to KO Spandam. Funkfried was in sword-elephant form with the trunk as a sword, then Franky threatened Funkfried to change his trunk back to normal "or else."
See, now this bit is important. And I wondered why I didn't recognize it. I only realized when I went to search for it, and found it, that I'd only read the spoilers for that week, and never the actual chapter trans/scans/raws
Right, that whole chapter kinda shits all over my theory, since the way Funkfried is being used is the same in this, as it is in the earlier instance I mentioned.
Now, there's still a bit of an inconsistancy here to my mind. Normal Zoans, as you say have their 3 regular forms. Full original, full new, and half way house. Funkfrieds form being used in these 2 instances is, according to you the half way part.
BUT I'd figured for a good while the form we normally saw, the sheathed form, was the half way one, because it looks like a sword, but has got several very definate elephantine (is that a word?) features. Such as the tusks, tail, feet forming the hand gaurd etc.
Now, the last time I brought this up, someone, I can't remember who pointed out that Chopper did keep the human capability to speak in even his full reindeer form, but thats not nessecairily a physical characteristic carried over, but simply a contrivance for story purposes or whatever.
So yea, I'm kinda torn now, because Funkfried still seems to be partially differant in how his powers manifest, but it could simply be story convenience being the reason in this case again, or something.
Oh well, time will tell I suppose.