well to be precise, an agency may still sue, but the debtor could very easily defend based on the SOL.
if you guys want to look through all the other legislation, feel free to use my bookmarks:
http://www.qp.gov.ab.ca/documents/Regs/1999_194.cfm?frm_isbn=0779743393
http://www.qp.gov.bc.ca/statreg/stat/b/04002_07.htm
http://www.ic.gc.ca/epic/site/oca-bc.nsf/en/h_ca02149e.html
http://web2.gov.mb.ca/laws/statutes/ccsm/c200e.php#98
http://www.gnb.ca/0062/regs/84-256.htm
http://www.gs.gov.nl.ca/cca/tp/collection-agencies/faq.stm
http://www.gov.ns.ca/snsmr/consumer/collect.asp
http://www.justice.gov.nt.ca/PDF/ACTS/Consumer_Protect.pdf
http://stage.cbs.gov.on.ca/mcbs/english/2692_3ea.htm
http://www.e-laws.gov.on.ca/html/source/regs/english/2006/elaws_src_regs_r06103_e.htm
http://www.gov.pe.ca/infopei/index.php3?number=53408
http://www.educaloi.qc.ca/en/loi/consumers/372/
http://www.justice.gov.sk.ca/problems-with-collection-agencies
http://www.gov.yk.ca/legislation/acts/copr.pdf
(funny I already had the link angella gave us, just never read it in depth =)