Good luck... It took me months before I got hold of a CF interface. Read: one that wasn't gone within 2 hours after being put up for sale.
From what I understand, Sunrise is planning to make a new batch - you might ask them if/when they become available again.
Another good option is Erikie's SD interface: cheaper than Sunrise's CF, and Erikie sells them built & tested. Only needs a housing (fits Konami case). Built-in software could be better, but it does the job. Better hurry if you want one of these! (see that ever-growing thread on this forum)