Try Company Store. They usually have every color in the rainbow.

I hope this works: try this - it looks like your color.

http://www.amazon.com/JS-Sanders-Thread-Egyptian-Yellow/dp/B00608D2G0/ref=sr_1_1?s=bedbath&ie=UTF8&qid=1363089067&sr=1-1

ARS22

If you don't find the right color, buy white sheets and dye them.

I was just at Homesense/Winners and saw some beautiful mustard yellow and grey bedding in a morracan print and it was onsale for 99$ (a 6 piece set). I realize they dont all carry the same stuff across the continent (Im in Ottawa, Canada) but it's worth a look, maybe.

Just saw a pic on Housetweaking yesterday that might be the look you are going for http://community.apartmenttherapy.com/contests/smallcoolkitchens/2011/entries/2879

that's the wrong link... http://www.housetweaking.com/

Bed has every colour of cotton sheets imaginable... www.bed-online.com

Zara Home has a couple things

http://www.zarahome.com/webapp/wcs/stores/servlet/product/zarahomeus/-15/80279977/562001/2015611/Geometric%2BStitched%2BBedspread%2Band%2BPillow%2BCover

I have one that exact same color that I use as a painting dropcloth...it was my mom's from the 70's. I like the combo with gray, though, more than the bright orange and avocado that she had:)

I just got some at Home Sense (Canada)...

Try dyeing them, but not with RIT. Dharma Trading has much better dyes.

I don't know what your budget is like, but dwell studio has beautiful (though expensive) taupe + mustard bedding: http://www.dwellstudio.com/modern-bedding-and-bath/duvet-cover-and-sets/draper-stripe-ash-duvet-bedding-set.html

Last month there were two back to back house tours where the master bedrooms both had the same gorgeous mustard bedding with black, grey, and deep blue accents. Kristy's Tropical Tudor and Cora Lynn Calter's Tour. Look 'em up. Not sure if the sources were listed or not.

http://www.coyuchi.com/
beautiful, organic, soft and just the color you want. I have the same color and love them.

I just saw some at west elm, like 2 seconds ago. The tab is still open in my browser! They call the color citron. Look in the duvet section too. http://www.westelm.com/products/stripe-sheet-set-b702/?pkey=csheet-sets

I've never heard of coyuchi, but so far it looks amazing. thanks for the tip!

Pottery Barn has this beautiful bright mustard duvet cover. I have it in my grey room, and it's gorgeous. http://www.potterybarn.com/products/matine-toile-duvet-cover-sham-marigold/?pkey=cpatterned-duvet-covers-shams

This looks mustard-y to me :)

http://www.target.com/p/threshold-paisley-comforter-set-yellow/-/A-14339383#prodSlot=large_1_11

http://www.bedbathandbeyond.com/product.asp?SKU=206911 this!

Dwell Peacock Citrine bedding is beautiful -- I have it on my bed and love it! It's even more mustardy than in the picture on the website.

http://www.dwellstudio.com/modern-bedding-and-bath/duvet-cover-and-sets/peacock-citrine-duvet-bedding-set.html

West Elm
http://www.westelm.com/shop/bedding/yellow-bedding/?cm_type=lnav

I was just in Target and their Threshold line had a pretty mustard duvet cover set with shams:
http://www.target.com/p/threshold-gully-paisley-duvet-cover-set-yellow/-/A-14287699#prodSlot=large_3_1

There's also a matching quilt:
http://www.target.com/p/threshold-gully-paisley-quilt-yellow/-/A-14339392#prodSlot=large_1_18

I think it would look really pretty to pair the duvet set with these sheets in the grey and white geometric print or striped sheets:
http://www.target.com/p/threshold-performance-sheet-set-pattern/-/A-14133369#prodSlot=large_1_13

This is a PERFECT mustard!

http://www.urbanoutfitters.com/urban/catalog/productdetail.jsp?id=20658639&parentid=A_DEC_BEDDING

I have it myself and it is the exact color of the swatch with this article. I cannot recommend it enough. I love it!