The straps holding the box were some that I bought at Performance Bike and they are designed for bike racks. Cost about $5 if I recall correctly. The box on my rack in the photo wasn't very heavy, just bulky, probably 2-3 lbs. I have probably carried more weight in my Rivendell Loafer bag, which is much smaller, with various items like lunch, tools, etc. The box was easy to carry and didn't affect handling much, but it always feels weird to me riding with my view of the front wheel blocked. That's one reason why I am not big fan of handlebar bags, altho they have their place.

My Salsa rack, which comes standard with the Casseroll frame, is actually more useful than the Nitto M12 because it is a little wider and more rectangular, so it's easier to lash stuff down to it. Too bad Salsa doesn't sell them as an accessory. This is one of the cool things about the Casseroll, which is an incredible bargain at about $500 for the frame, fork, seatpost clamp and front rack. They used to also include a matching Salsa stem until they quit making them.

I will post another photo later of the rack with my Rivendell Loafer bag attached. Surprisingly, there are very few options for bags designed to fit Nitto M12 racks, even though they have been around a long time. The nicest ones I have seen are Zimbale, and they are less expensive and appear to be better designed than the Rivendell ones.

http://www.zimbalenorthamerica.com/