I do own a vintage Martin - a baritone (pic below) - and I'm currently on the prowl for a tenor. I also own 5 vintage Martin guitars. Contrary to popular belief, nice vintage Martin ukes can be had for fairly reasonable prices, although, of course, your definition of reasonable may differ from mine, and, you will have to be patient, do your homework, and be ready to pull the trigger when the opportunity arises. Given that prices for tenor Mya-Moes or Collings or Moore Bettah's, etc, can easily run $1200 to $2000 or more, being able to acquire an expertly crafted Martin tenor uke in great condition for less than a grand seems like a pretty good deal to me, and sopranos can be much less than that, the rarer concert model a little more. Most issues in vintage Martins, and others, involve cracks, which are inexpensive to have professionally repaired and do not alter sound quality. In the world of vintage guitars, cracks are almost a given and while collectors certainly covet pristine crack free instruments, cracks are pretty far down on the list of major structural or tone killing issues and are not deal breakers unless they involve the headstock or neck itself. While many would argue that today's Martin instruments do not measure up to the standards of those built from their inception through the 50's or 60's, those that were built during their golden era are among the finest instruments ever built in the world, bar none, and are still a relative bargain in my humble opinion. Not overly fancy in most cases, but the attention to detail and exquisite craftsmanship are clearly evident from a bygone era when Martin set the standard for excellence in building first rate musical instruments. Obviously, if you desire a uke in something other than mahogany, and occasionally koa, then vintage Martins may not be for you, or, if you want more bling, you can get certainly some of that in the higher series Martins, but it will also cost you accordingly. I personally think the basic series vintage Martin ukes are elegant and classy enough in their simplicity.
Basic vintage Martin uke info:
http://www.geocities.com/~ukulele/martin.html