F. Schumacher! If you're DIYing the vestments, you might have to look at how you could procure these fabrics (since you're not "in the trade") but if it's a large order I think F. Schumacher would make exceptions.

Do you have a parishioner who is an interior decorator? The best fabric always seem to be "to-the trade" only. You also might find some remnants on ebay.

If you have a business, you are part of 'the trade' and just need to get the necessary tax documents to back you up. Then, the whole world of 'trade only' opens up to you.

@DULCIBELLA - Good point. I assume he works for his church, though. There are tax documents for churches, but it doesn't make them businesses.

Father Daniel, consider working with a professional weaver. There are more of them than you think, and there are probably several of them in your area. Contact your local weavers' guild to see if there is anyone who does the type of work you are looking for. I belong to a mid-size guild and we have probably 4-5 professional weavers. We have weavers with the equipment and skill to work with fine silk threads and very complex designs. You could see what they have "in stock" and even commission something to be exactly the way you want it.

I don't think Jesus ever wore anything "high end"

Depending on your location in the country, I'd highly recommend making a trip to New York City. There are many, many fabric stores that stock the labels that are usually "to the trade only" for retail sales. I'd be willing to bet there are even fabric/notions stores that are specifically catered to the churches/religious garment makers.

Frankly I'm starting a countdown for the deletion of Gypsymomma0911's comment...

Really, Father, you should know that Watts is the only place for proper fabric.

http://www.watts1874.co.uk/

I think Gypsymoma0911 has a valid point.

I'm pretty sure Jesus also didn't judge people, especially not in anonymous blog comments.

I concur with undamaris, that the only source for vestments is Watts.

Padre,
If you can't get to NY or LA's garment district, then your best bet is online.
A few sites to check out:
fashionfabricsclub.com
denverfabrics.com
www.goodorient.com
http://www.fabric.com/home-decor-fabric-table-top-fabric-brocade-clergy-fabric.aspx

Or even Amazon

Happy hunting.

www.thaisilks.com, based in Los Altos, CA. I've been buying from them for more than 15 years. You can sign up to get their entire swatch book. Not surprising, many of their silk blend brocades have an asian theme, but many are paisley or geometric.

http://www.thaisilks.com/product_info.php?cPath=1_12&products_id=303

Try Designer Fabrics in Toronto. They carry everything and designers are a big part of their clientele.

designerfabrics.ca

ebay.

http://www.aheavenlystitch.com has liturgical brocades--high and not so high end. They will also search for fabrics if they don't have what you want. I have not dealt with them.

La Lame, Inc is THE place for high end brocades, lace, trim, etc. They are in NYC but do mail order. I used to make costumes in NYC and still have some scraps of their fabrics as theatre designers use them a lot also.
http://www.lalame.com/

Also
http://www.scalamandre.com/
Scalamadre, though not liturgical, has high-end velvets, brocades etc--beautiful fabrics. They generally sell only to the trade, so you may need, as others have mentioned, a wholesale account and/or interior designer connection.

Hello Father Daniel, we are fabric wholesalers, and we have a collection of religious brocade that are very good quality and at affordable prices. Please let me know if you are interested, we are happy to send you samples. My email: czy180@gmail.com.

p.s. We also have other designed brocade (brand new design, we are trying to move away from the typical asian themed patterns).