Me too. I almost bought it but the price put me off. I created this for less than half the cost and weight using a Ti rack, zip ties and Sistema basket.
I have a Chrome Vega bag converted for Brompton use with a smaller front carrier frame. It's a low-key, robust bag even if it does have c.2007, Dell laptop bag vibes. 15L is a good day bag size for me.
I'd go Tru-Blu:
http://www.wrhpv.com/smalltyreshop/index.htm#!/TruBlu-tyres-40-349/p/456739386