Okay, I'll admit to being a groupie. When I first discovered TB, I was feeling especially poor, so I thought I'd make my own bag. The pix don't do justice to the lining, which was the closest I could get to Wasabi - but mine has polka dots. And I used a snazzy red to line the front pocket.
What did I learn from this experience of reverse-engineering a TB bag? The ones you can buy are worth every penny! First, it's really hard to find the right fabrics. I did okay with the plum cordura, but couldn't find anything cool for the lining so I ended up using cotton. That's far from ideal in terms of holding the shape, although it's pretty cute. By the time you buy fabric and fittings, the cost is creeping up (although I was able to canibalize the straps and hooks from other old bags I didn't want). Second, it takes a looooong time to make one of these! It would probably go quicker the second time, but I haven't attempted it again.