Ross Purrity. Sedreck Fields. Both of them have been in the ring with 6 heavyweight world champions. Ross drew with Morrison and TKOd the younger Klitschko, and Fields took a decision over Shannon Briggs.
Anybody with decent management will fight on old guy or two on the way up. Some my most respected are Gatti, Barrera, Morales, Augustus (who had no management) and lately Paul Williams. For the most part they have all battled whoever was put in front of them.