Not sure how unheard of these guys are, but I'm sticking to those who haven't played internationals yet.
Sean Marsh (WA) - Quite talented, hailed by Steve Waugh as a future Australian player. Has so far not quite lived up to his billing with a FC average of 30, but has a fair chance given his reputation of playing for Australia if he has a good season or two. 22 years old.
Mark Cosgrove (SA) - Despite being dropped a couple of times last year, really showed a bit on a couple of occasions, and is someone to watch next year. Only 21 and seems to be improving, FC average of 31.
Daniel Cullen (SA) - Had the best debut season for a spinner in Australia for a fair while. Got some attention with some good performances through the year, and earned himself an Australian contract with a big finish, putting in three big performances in a row, including 8 wickets at the WACA and 9 at Hobart on the two least spin-friendly surfaces in Australia to finish the season. Only 20, and may even possess a doosra.
Phil Jaques (NSW) - Obviously had some attention on this forum, but has really exploded on to the scene in the last year. Was dominant with the bat last season for NSW, and then had a very successful stint with Yorkshire in the CC, and has boosted his career FC average up to 55. Just a few days ago in his first Australia A appearance, carried his bat for a near-century in difficult batting conditions. 26 years old, and a clear candidate for an opening position in the test side soon.
Cameron White (VIC) - Was the "new Warne" at the start of his career, but quickly became the butt of many jokes when he didn't quite live up to his billing. Still, has proved quite adept as captain of Victoria, and while his flat, quick leg-spinners aren't as penetrative as they might be, his batting has improved noticably in recent times. This improvement in his batting and some good showings with Australia A might yet earn him a place in the Australian ODI team as an all-rounder, and at only 22 he has a lot more experience at first class level than most cricketers his age. Averages 27 with the bat and 34 with the ball in FC cricket.