If you don't have enough of the oak to do the boxes, consider using a mix of other woods with it. Contrasting woods usually look best together. Depending how much of the oak you have, use it for tops and bottoms, or ends or sides. If you use something light for the sides like maple, the oak stained very dark could be very attractice. You could even order the maple used for drawer sides that are between 3/8ths and 1/2 inch thick. Use a little of the maple to make a handle on top to emphasize the contrast. Make the box just right to hold a locking diary and add that in with a great pen. They will go over well.