SInce I do 95% of all sketching, inking, and drawing the old fashion way (non-digital) I still use some old tools of the trade. On the left is my current pen/stuff carrier I bought at Blick's. It's a soft case carrier that can hold a surprising amount of tools inside.
However on a recent trip to Tokyo I "splurged" on a hand made leather pen carrier that almost wants to be a wallet too. It's from Wolf & Dog. a small, Tokyo-based leather working company. Check out the link, it's pretty cool (it's almost all in Japanese).