Basically my whole wardrobe is one giant MOTG capsule. I like the idea of canvas and denim jackets, but they are exclusively warm-weather toppers for me. Cotton jackets don't provide much insulation or weather resistance. This time of year, for me, it's all about puffies (like Rachy suggests) and upgraded hoodies. I have an old solid black merino hoodie that I love, and also a black softshell jacket with moto styling that is both functional and kind of cool looking. You could also think about chunky cozy cardigans -- like Aran-style fisherman sweaters and such -- used as toppers. And, heck, blazers with jeans! I'm always having to remind myself to bring the blazers out on the weekends.
For jeans (and really just pants in general), I like something loose enough at the bottom to cuff/roll, that way you can wear them with lots of different shoes and boots.
Speaking of which -- What is your weekend footwear situation? I think shoes are really make or break with MOTG outfits. I think you absolutely need something that is distinct from your workwear shoe style (whether thats pumps, ballet flats, whatever), but is also not a straight-up gear shoe. I'm so not into wearing my running shoes round town (they're too muddy anyway!). So, some sort of classic/iconic sneaker, or casual ankle boots, or a funky loafer/oxford -- kind of depends on your style, but if I were approaching this as a capsule-building exercise, I would probably start with the shoes and work up.
