Blizzard forum poster Hortus has announced that premade characters are now available for copy to the PTR for patch 2.4.3. The Character Copy page says that the average wait time for copying is five days, but I've never waited as long as the estimates for my copied toons. I copied mine to the PTR tonight and will let you know how long the transfer takes.
The eighteen premades are all Level 70s, two of each class (one Horde, one Alliance). Undead comprise the largest race (5), followed by Dwarves (4), Gnomes (3), and Orcs (2). There is one character each for Tauren (Druid), Night Elves (Druid), Blood Elves (Paladin), and Draenei (Shaman). They are all specced with gear made for PvP, judging by the character names. So what are you waiting for? Maintenance starts soon! Get out there and copy a premade character -- or four -- for yourself.
[Thanks, Josh and Philip Stetson.]