Hello,
In Amsterdam we have a couple of shops that will sell big ladies shoes.
The http://www.vanharen.nl/NL/nl/shop/welcome.html ( a http://www.deichmann.com/DE/de/shop/welcome.html shop ) sells some , but the quality is not so good.
This is a "regular" shoe store with about 500 models for regular sizes and about 50 models for size 43/44
There is also http://www.stravers-shoes.com/, but again I dislike the quality.
This is a speciality shop for small to large sizes.