Here are some useful links for church needlepersons:
Ecclesiastical suppliers in the UK who sell fabric:
Watts & Co.
Mary Collings
F.M. Church Supplies
Juliet Hemingray
Croft Design Church Shop
Ormsby of Scarisbrick
Vanpoulles
Wippell's don't, I think, sell fabric, but they have a useful set of information sheets on the fabrics they use for making up vestments
In the US:
Ecclesiastical Sewing
Another collection of useful links:
Anglicans online - vestments