Menards is our biggest supplier, and lumber and steel for roofs hasn't been noticeably impacted.

They also had all their suppliers lined up and were one of the biggest purchasers in the area at the time.

Make sure to get several references of current and past clients, at least 5 each and call them.Get a copy of the license and insurance.Talk to subcontractors and suppliers and make sure they are paid on time.Check the job site for cleanliness and organization and quality.Make sure to take title to the properties in an LLC and have your attorney draft all the paperwork and partnership agreement before you do any business. 

@Anthony ZottoHi Anthony,If you want something that's not a pie in the sky click bait title book maybe think aboutMultifamily Housing: A Comprehensive Guide for Investors, Developers, Apartment Professionals, Suppliers and Students.It's by the National Apartment Association, and while not an investment advisory hoopla rah rah type book, it does provide a lot of insight into the industry.Also, it's not cheap. 

Along with our door and finsih materials.. in our area one store does all flooring and counter tops.. they design it for you and install. etc etc. thats the only way you can get any kind of scale building you need pro's to get the jobs done in a timely fashion trying to drive around and save 50 bucks is a very poor use of your time.One thing i will do is at our big appliance suppliers they will have a yearly sale of their last years models on high end stuff. 

Is anyone aware of a list provider for Canada similar to List Source for marketing?  If so, can you provide details and your experience and best practises using?

There are multiple suppliers of credit reports.

How about your local suppliers?

The alternative is use another supplier and get a cash value from home warranty.   

In my area granite suppliers are some of the most reliable and easy to deal with contractors.