Neutral preamplifier recommendation $1K new

Looking for a unit that measures well & has no/little sound of its own. 
 

No such thing. Forget it. 
Instead I would drop the XLR requirement and look for the best sounding preamp for $1000. 

@audphile1  Do you have a recommendation?

Yes. $1000 used Rogue RP1 actually insanely good preamp. Quiet, transparent and you can tailor the sound by trying different tubes. 
Has great phono stage built in. 

OP...for about that money you can audition and purchase a Hornshoppe Truth line stage. I don't believe Ed has balanced connectors available for it. Regardless of that it would be extremely difficult to beat it balanced at any price point. 

I've fiddled around in this hobby since the late 60's and have never heard any component get out of the way like this one. It just does its job with zero sonic signature that I can perceive. I had mine built with just a single input eliminating the selector and necessary connectors. Perhaps allowing a minorly cleaner presentation.

The standard Truth is a 0 gain unit however, I know Ed offers a 6db gain version which I haven't heard.

Perhaps it's worth investigating.

      LP

Oh...one more thought. Don't let the cosmetics scare you:)