You probably won't want to go 44-deep, like I did. And it's not at all necessary, since the objective here is to establish some reference points for the Top 40 that will be upcoming. So list as many or few as you choose. I just thought that it wouldn't hurt to get all (or at least, most) of the names out there, so you can make your own judgments.
The ages are according to the current listings (for 2010) on baseballreference.com
1. Aroldis Chapman, 22, LH
2. Jacob Johnson, 19, RH
3. Ismael Guillon, 18, LH
4. Jonathan Correa, 19, RH
5. Matt Maloney, 26, LH
6. Jordan Hotchkiss, 24, RH
7. Kyle Lotzkar, 20, RH
8. Sam LeCure, 26, RH
9. Ben Jukich, 27, LH
10. Daryl Thompson, 24, RH
11. Drew Cisco, 18, RH
12. Daniel Corcino, 19, RH
13. Matt Fairel, 22, LH
14. (John) Wes Mugarian, 18, RH
15. Daniel Tuttle, 19, RH
16. Luis Gonzalez, 17, LH
17. Matt Klinker, 25, RH
18. Josh Ravin, 22, RH
19. Tanner Robles, 21, LH
20. Scott Carroll, 25, RH
21. Abel De Los Santos, 18, RH
22. James Avery, 26, RH
23. Brad Boxberger, 22, RH
24. J.C. Sulbaran, 20, RH
25. Pedro Villarreal, 22, RH
26. Radhames Quezada, 19, RH
27. Mitchell Clarke, 19, LH
28. Elizier Beard, 19, RH
29. Jose Guzman, 18, RH
30. Wandy Peralta, 18, LH
31. Mark Serrano, 24, RH
32. Evan Hildenbrandt, 21, RH
33. Stalin Gerson, 21, RH
34. Clayton Shunick, 23, LH
35. Dallas Buck, 25, RH
36. Tom Cochran, 27, LH
37. Chad Reineke, 28, LH
38. Justin Walker, 23, LH
39. Oswaldo Mieres, 18, RH
40. Travis Webb, 25, LH
41. Curtis Partch, 23, RH
42. Tim Crabbe, 22, RH
43. Cesar Caceres, 21, RH
44. Jesus Adames, 19, RH