This would probably receive more responses if this post was in the mortgage forum.
Why not call up a bank, a credit union, and a broker and ask them? Will the tiny home be on wheels to be moved from one location to the next? Or do you plan to park it (more or less) permanently on a piece of land?
The mortgage forum may be of more service, or surely, with their popularity...a tiny house forum has to exist somewhere.
I'd imagine if it has wheels and/or is able to be easily moved it would be considered a mobile home. Only experience I have with that is my uncle's home in a retirement community was considered a "vehicle loan".
I haven't done it, ut I'd like to someday. It is usally classified as an RV and often the builder must have a particular certification. I forgot what this is called (RV certified builder). I believe there's 2 certifications.
Unless the axles, wheels and so forth are removed in my state its considered a car and has a car title no home.
Many of these "tiny homes" are called park models. They can be financed similar to a manufactured home (since they are made to the same specs). There are some stipulations to them, at least to the one or two I've done. The down payment is usually 20% and right now, the two lenders I have that do them finance only in Arizona and California.