Hve you condsidered making it yourself?
I made some walnut ones to accomodatesome larger 8mm pens.
The customer wanted a darker walnut than what I could find available.
I used a 3/4 bull nose router bit and 5mm barrel hinges.
Jeff,
The one I made for my wif'e pen set (can be seen in my album) only took me 2 evenings. If you have a router table with a round-nose bit, it doesn't take very long at all. I got the hardware at the local ACE hardware store.