According to the Feature Navigator available on CCO, there is no support for the Multiclass Multilink PPP feature on the 7500 platform.
http://tools.cisco.com/ITDIT/CFN/jsp/index.jsp
Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México