You might want to check into the Triple-C Leather Company. They can manufacture laces in any width, thickness or color you want. One drawback- while their bulk prices are excellent, sometimes you have to order large quantities to get that price. But, they might be worth a look. you can request lace samples from them. I did that last year. It took a long time for the samples to arrive, but they eventually did.
http://www.triplecleather.com/
Here is a source from eBay that might help you out. I've ordered some laces from him before and they were pretty nice. His 3/16" laces are just a little less wide than others, maybe closer to 5/32". He used to offer a lot of different colors, but from his latest ads I'm not sure if he still does.
http://stores.ebay.com/Wood-N-Stuff
Yennaco Custom Gloves sells a wide variety of colors. They are 1/4" wide, though. And they're not cheap- $6 for a single lace! But if you're looking for an odd color, they probably have it.
http://www.yennacocustomgloves.com/ycgload.html
The Batters Box is a baseball supply store that has a few colors of lace- again, all 1/4" which is probably too thick for you. Their laces are pretty good quality. I had to order some navy blue from them recently to relace a Mizuno Pro/Ichiro glove.
http://www.aluminumbats.com/index.asp?P ... ProdID=929
I know from the emails we exchanged in the past that you have used the Tandy laces that come in a spool, which is a 5/32" wide lace. Something I've had some success with is buying their lightest colored lace and dying it myself. You can buy leather dye in just about any color, and wool applicators to apply it. It's simple to do and with a little practice you can quickly come up with laces in any color you want. I use a water-based dye as it is easier to work with and clean up. I'm thinking of trying this with some of the white laces from Tanners (where I'm sure you have bought laces before).
One more- I have bought some great laces from forum poster Glove-Works. I'm not sure if he really wants to be in the lace supply business (if he does, it would be nice to add his selection to his web site!). I guess you would have to ask him and see what he says.
http://www.glove-works.com/
If anyone else has any sources for laces- whatever color or size- feel free to chip in! Laces are one thing that just about every glove collector would be interested in finding new sources for.