I got my Scamp 13' a year ago and when first registered it was classified as a "Trailer Coach" by California's DMV. After seeing a couple of postings on other forums, which stated that is should be classified as a "Camp Trailer" instead, I went back to DMV, where I asked for a re-classification. The DMV inspector agreed, as should have been from the beginning, and reclassified it as a Camp Trailer. What does that mean? It means that it can be registered with the Permanent Trailer Identification (PTI). Instead of paying over $200 per year for registration, it cost me $20 for five years. If you want a paper title, you can pay an additional $21 (one time), which I did.
Bottom line: In California, if you register your Scamp that does not exceed 16 feet you should be able to register it as PTI and save a lot of money.