Can anybody think of a source for an adapter cable that will take a single XLR line level signal and attenuate it down to a consumer line level signal and then terminate in a male, stereo, mini-plug? I want to attach a SoundDevices MM1 to a little consumer digital recorder. I do have the necessary adapters and barrel attenuators to make this happen, but I want to get it down to a single cord. If there is not already an existing product, can someone recommend a custom cable builder who could make such a thing?

It might be a squeeze to get all the components into an XLR plug - because I assume the XLR line is balanced, and you want to go to 3.5mm unbalanced - or did you mean stereo as in TWO XLRs down to a stereo 3.5mm plug? If you use the 1/8W resistors, they can just be squeezed in, and pretty well anyone who can solder could make these up - there are bound to be people local to you - if you know any radio hams, they are often very good at this kind of thing. I've never seen one off the shelf.

I know B&H has cables and plug in adaptors that are made for this purpose. Did you look there?

Markertek in Saugerties, (Woodstock NY area) Markertek Custom Cables (http://www.markertek.com/custom/cables) makes custom attenuation cables, per your or general attenuation parameters.
FWIW, 'Markertek', aka 'Tower Industries', bought Sescom when owner/audio electronics engineer Franklyn Miller passed a few years ago.. I had previously met Franklyn and had the pleasure of working with Tower Industries/Markertek president/owner Mark Braunstein on a movie. He and the folks at Markertek are good people!

I often get Custom Cables made at Professional Sound Services in NYC. Pro-Sound.com ~ Professional Sound Services (http://www.pro-sound.com/)