Bit of an old post but I'll second joquarter's remarks:
- Boomsma.nl is pretty good, I used to mail order from them but visited them 2 days ago. Family run business who really take the time for you and have a lot in store: leather, tools, chemicals you name it. Everywhere I looked I got the "I want that, and that...and that!"-feeling.
- Lederhandel Berten: I ordered 1 hide from them some time ago, little cheaper than Boomsma. I requested pictures of the hide and they even sent it to me, while they were moving to a new location. So pretty good service there and a good hide.
You could also contact Martin Swinkels to ask for a good adress: http://martinsheaths.blogspot.com/
Regards,
Thijs