Also, I tried to get my hands on some Stellar footrests but so far couldn't find any distributor who would order them for me. I wrote 2 emails to Stellar directly but didn't receive an answer either… Any hints there?

For Stellar, write or talk directly to Dave Thomas or Ed Hofmeister.
http://www.stellarkayaksusa.com/usa/Contact.html
They are based out of the US headquarters in Massachusetts. I've had great luck dealing with both of them. It can take a day or so to hear back, especially if there's a big race, show or other event. Tell them I sent you.

I have been pretty unsuccessful searching the web up and down trying to find a canadian online store for cords, bungees, footrests, paint, dyneema cord, stainless/aluminium hardware etc. all the things necessary for finalizing my kayaks…

Have you tried Noah's Marine (Ontario)?
http://www.noahsmarine.com/index.asp

There is also Newfound Woodworks (New Hamsphire)...
www.newfound.com/accessories.htm

and Chesapeake Light Craft (Maryland).
http://www.clcboats.com/