Use the Google Custom Search in the Search dropdown menu to search for Burro
trailer. You will get at least two if not more threads in which there is discussion of three production facilities of two separate Burro companies, dates when companies were active and some speculation as to production numbers. You may find mention of a history of Burro trailers which, to my knowledge, has not reached publication and so not available at this date.
In the "document center" of this site, you will find a PDF of a 1981 sales brochure for the earlier of the two companies which used the "Burro" name. There are also PDFs of assembly manuals for the diy "kit" version of the 13' model. This first incarnation of Burro trailers is usually called the "Sac City Burro" in reference to the Iowa town where produced. From recollection, I believe this Burro was made for at least a decade or more beginning in the early 80s.
The more recent Burro design was produced by Burro Trailer Co. LLC in Escondido, CA for 3 of 4 yrs. begnning in 1998. At least one member here has speculated that not more than 60 Escondido Burros of all models (13', 14'WB, 17'W
were produced. Without doubt, the total production figures for Sac City were much higher.
Go to www.burrotrailer.com
where you will find the sales site for the later company. This company, as stated earlier, has been out of business since 2001 or 2 but many folks believe it is still in business because the site is still up. The site is a neglected "fossil" but the information it contains about trailer models, configurations, and prices is very nearly all information that is available about the latter company with the exception of word of mouth and trailers still in operation. As you will see, this company also offered a lower-priced kit version.
For "planespotters" the big external visual cues for identification are the prominent two color logos (which have often been removed), the vertical seam between halves. In the interior, a molded inner hull or "liner" (there are other marques which share this build feature). The distinction between Sac City and Escondido trailers is quickly obvious in the molded in tail and running light
"stalks" or nacelles on the former vs. recessed tail lights
and an overall "cleaner" look to the Escondido. The Sac City should have a door of molded fiberglass. All Escondidos have a flat door with a frame of aluminum extrusions and a hollow core panel comprised of softwood framing and lexan or polystyrene skins.
To my knowledge (or lack of same) all variants of Burro trailers have a leakproof and structurally sound vertical seam; the central "Trimlok" mold on the vertical flanges are purely cosmetic "finish". All thruhulls (windows, roof vents, air conditioners) will of course eventually leak but these leaks
are not attributable to a defect in the prominent vertical seam.
Hope this gives you some ideas where to learn more. My opinions are only mine. Presentation of facts and dates and my expresson of ideas may well warrant emendation and correction.
See Per got here first with the goods and the accent on some good features of the donkeys. Per knows of which he speaks!