A Tenor Ukulele has a scale of between 41 and 46 cm (16 - 18 inches) and the usual length is 43 cm (17 in). The Tenor first appeared in the 1920's with this scale length as Martin introduced a 4 string version of its Tiple Ukulele and Gibson followed this lead, (Other makers at the time used a different, smaller definition and some even called this size Bass). Nowadays this is the most popular scale length after Soprano and most makers have some in their range. Top Luthiers seem particularly fond of making them and they often are very imaginative in both shape and decoration.
There is a subset of the Tenor size called the Jumbo Tenor. Unlike the subsets of the smaller sizes, this doesn't have a longer neck or any particular playing difference, it's just a big Tenor going into the Baritone scale, (but usually it is still on the smaller end of the Baritone Scale), but still tuned like a Tenor; Only a few manufacturers make Jumbo Tenors.

Here are some Tenor Ukuleles I would like to have at Ukulele Corner
Click on the Ukulele for a longer list

Marshall Stapleton Selmer Style Ukulele
Craftsman Made
like this Marshall Stapleton

Kanile'a Islander cutaway Tenor at Lardys Ukulele Database
Mass Market
like this Islander

Albo Radiotone archtop Tenor Ukulele
20th Century
like this Radiotone

Paul Celentano Atom Tenor Ukulele
Pineapple or other shape
like this Celentano

Pendennis Mini Jazz semi-acoustic Archtop Ukulele
like this Pendennis
Beansprout Tenor Banjo Ukulele Banjolele
like this Beansprout
Ron Phillips Metal Guitars Resonator Tenor Ukulele
like this Ron Phillips