Here is a list of everyone who has ever broken 13:00. 63 people in all. Of those 63, 9 have tested positive for PED or are highly suspicious (Kennedy included by virtue of the era in which he broke 13:00, and the people he trained with, Lagat because of that pesky "A" sample). That widdles the list of sub 13:00 down to 52. My suspicion is that it would go closer to 40 with better testing.
Sub 13:00 doesn't happen every day for a clean athlete. Its still a very notable achievement. If the US could get 3 clean guys on there in the next few years, that would be amazing. I think it can happen between Teg, Solinsky and German. Possibly Rupp too, but time will tell.
12:37.4 Kenenisa Bekele
12:39.4 Haile Gebrselassie
12:39.7 Daniel Komen (*)
12:46.5 Eliud Kipchoge
12:47.0 Sileshi Sihine
12:48.7 Isaac Songok
12:48.8 Saif Shaheen
12:49.3 Brahim Lahlafi(*)
12:49.7 Mohammed Mourhit(*)
12:49.9 Paul Tergat
12:50.2 Hicham El Guerrouj
12:50.3 Abderrahim Goumri
12:50.6 Moses Masai
12:50.7 Moses Kipsiro
12:50.8 Salah Hissou(*)
12:50.9 Ali Saïdi-Sief(*)
12:51.0 Joseph Ebuya
12:52.0 Thomas Longosiwa
12:52.3 Sammy Kipketer
12:52.4 Edwin Soi
12:52.5 Tariku Bekele
12:52.8 Gebre-egziabher Gebremariam
12:53.0 Abraham Chebii
12:53.4 Khalid Boulami(*)
12:53.7 Augustine Choge
12:53.7 Philip Mosima
12:53.8 Assefa Mezgebu
12:54.1 John Kibowen
12:54.1 Dejene Berhanu
12:54.2 Abreham Cherkos
12:54.5 Moses Mosop
12:54.6 James C'Kurui
12:54.7 Dieter Baumann(*)
12:54.8 Moses Kiptanui
12:55.0 Benjamin Limo
12:55.5 Hicham Bellani
12:55.6 Abebe Dinkesa
12:55.6 Mark Kipkinyor
12:55.8 Craig Mottram
12:55.8 Boniface Songok
12:55.9 Tom Nyariki
12:56.3 Ahmad Abdullah
12:56.3 Paul Koech
12:56.5 Luke Kipkosgei
12:56.7 Richard Limo
12:57.0 Mulugeta Wendimu
12:57.1 Boniface Kiprop
12:57.2 Worku Bikila
12:57.8 David Chelule
12:58.2 Bob Kennedy(*)
12:58.4 Saïd Aouita
12:58.5 Yusuf Biwott
12:58.6 Hailu Mekonnen
12:58.6 Mike Kigen
12:58.6 Moukheld Al-Outaibi
12:58.8 Ismaïl Sghyr
12:58.9 Paul Bitok
12:59.1 Jonas Cheruiyot
12:59.2 Bernard Lagat (*)
12:59.3 Zersenay Tadese
12:59.4 Million Wolde
12:59.6 Ali Abdosh
12:59.8 Leonard Maina