Mostly correct, ukulelekarcsi, but I might add a few minor corrections: the standard models, basically most of the numbered ones, do not have an arched back, but rather a flat one. The only exception was the number 4, all made of maple, which was available with a sunburst finish or, alternatively, which just a straight natural one.
Talking about the numbers: the 1 and the 4 were made of maple, but the 1 had a flat body and was all colored black. The nr 2 models were mostly made of maple, but sometimes also of mahogany, they had a characteristic branded palm tree and beach design on the cover, and the back was all colored, red, blue or green. The number 3, on the other hand, was made of Gabun, or rather okoumé wood, and mostly made with a sunburst finish, although the so called 3A had a natural one, as well.
The 5 and 6 are both still available in a flat, i.e. travel, version.
And the nr. 7 had a spruce top, but a body made of ovankol, and later on, as ovankol in good quality was getting rarer, of zebrano wood. Today, the line is abandoned, as are the nrs. 2, 3 and 4.
The 9 is actually called tenor by Brüko, but it has the same body size as a Brüko concert, with a tenor scale. The tenor neck, however, has only 12 frets, as the standard soprano models (with a longer scale, of course!).
But it's absolutely correct, that most of the numbered standard models are largely abandoned today, and they are focussing much more on producing custom models of various, high class woods. They started a line of Pineapple-shaped models this year, also made of various woods. They updated their website also this year. So now you can find most of the instruments on offer there. However, it's always worth contacting them, as they often have a number of instruments which don't make it on the website. They are very lovely and helpful, so far I went there twice - it's a roughly two-hour drive from my place.
Oh, and they used nylon strings until about ten to fifteen years back. Since then, it's fluorocarbon. Still by the German string company Pyramid.