I love the design but I too agree it is a bit large. Granted larger gives the driver the preception (sp?) that you're a larger bike on the road but at the cost of clunkieness.
I like it if it was smaller a bit. Perhaps have the rear unit split into two units with a attachment for those with racks and also have a bar for those without racks so you can mount the whole unit as one. If you're having a hard time picturing what I'm trying to say about the back signals what I mean is |_ _| to make the unit more configurable.
I wonder how much they want for the unit. I see all the suppliers as UK shops. Oh wait. my bad.. the original link said ~$80ish. So I'm guessing that's like $160 CDN then with the exchange rate.