I think if you ask for "Avaya certified" cabling you are setting yourself up to pay a lot. Just make sure that you cabling is up to your local electric/telecom code and I would look for a BISCI certified installer. Also Avaya is not the one who drives cabling standards. It's the TIA/EIA
Also stick with brand name parts. Siemon, AMP, Ortronics, Leviton, Hubble, Panduit. I would use cable from Mohawk, General, Comscope, etc. All brand names should provide you with years of trouble free service. Some companys offer a 25 year warrenty with a certified install. I use the Siemon/Mowak soulution.
Look here for more:
http://www.bicsi.org
http://www.tiaonline.org/