I was looking for other options besides a canvas tote bag and found a really cool site that has all sorts of types of promotional products. They mostly serve conference/event planners -- so they are the types of things you would get at a conference, which could be really cool.
I found these cool messenger bags -- they are slightly more expensive than a canvas bag... but I think they could be very cute.
Or how about this one that is currently on sale:
I could totally see you putting a travel mug in there... and then clipping a key holder to that caribeaner...
Anyway...
Have fun... if you are promotional product geeky like me, you'll love this site:
Printed Promotional Products, Advertising Specialties, Custom Imprinted Promo Logo Items, MARCO