I think this has already been posted elsewhere, but wanted to mention that the cabinets at the Mattamy Design Centre are from Canac.
http://www.canackitchens.com/
There are several Canac showrooms in the GTA. We visited one in Oakville (490 Speers) and it had several model kitchens for us to look at. The one in Mississauga (1825 Dundas Street East) has a smaller showroom, but they had a nicer big catalog. There were small catalog/brochures they can give you to keep that we took. I wish Mattamy would give them out too because they had some nice info on the Ultra/Signature/Cellina lines of cabinets. It has a chart/spreadsheet showing exactly the ultra/signature/cellina levels are and what profiles/types are in each level.
We're contemplating multiple options right now. Not sure yet if we're going to go with the Mattamy upgraded kitchens (pricey) or maybe just go with mattamy standard kitchen and then upgrade it ourselves later. Or get it partially upgraded with mattamy, and then other upgrades like the molding option, etc, pay Canac directly to add it on after.
Be careful when talking to Canac about prices as some people mentioned they might not give you prices if they know it's in regards to Mattamy as they may have some special arrangement with Mattamy to not give price quotes on their exact kitchen layouts (that's what some people have mentioned in emails).
Btw Jason Gunn at GunnandCompany Woodworking Ltd., 905-569-2602 does custom Kitchen cabinets as well as other work. Krista & Jay are online and Jay mentioned possible discounts to Hawthorne Villagers. They're work office is actually fairly close to the mattamy design centre.