$7000 preamp vs $700 receiver - Is the difference THAT significant?

I wanted to suggest something else from the likes of Pass Labs, Luxman, Accuphase etc. other than Mcintosh but after reading this remark of yours

"I’d like... no, want... no, desire... to add "Blue Meters" to my setup. McIntosh haunts me. For dozens of years."

I think you better go ahead and get that dream of yours since it has been haunting you for dozens of years. Life is short, just get what you desire if it is within your financial capabilities and enjoy the finer luxuries of life. As others have aptly advised, it is true that there will be a difference. Other aspects such as matching of amp to speakers and placement of speakers in the room will be important as well.

Just to add, if the sound quality of the Mcintosh doesn't wow you too much, the high build quality will likely do. You will then realize you are getting your money's worth.

McIntosh makes really nice American gear. They use high quality components that make sense, and can be sourced around the world if needed. They’re not designed by some yahoo that will smolt exotic metal that nobody will be able to figure it out when he dies (God bless these guys). McIntosh amps stand the test of time as legacy pieces in high end market.
Perhaps if you provide some more specific information about listening preferences @stereo5 might be able to help with a more specific suggestion. He’s a knowledgeable McIntosh guy and is easy to talk to.

Just curious.  The OP is interested in McIntosh.  At one time this manufacturer was making AVRs.  At the same time they were making Integrated Amps.  Now, there is a tremendous prejudice by some posters here against AVRs, the statement being that they are inherently poor sounding compared to separates.  Now shouldn’t the Mac AVR just sound like the Mac Integrated with a Tuner added under the bonnet?  Does adding such a tuner section inherently degrade something from being “high end” into transforming into crap?  And if so, why?

For some hobbyists, sound quality is not always the  highest ideal; they must have the visual experience to be satisfied. To pursue the best sound regardless of peripheral features, one must be ready to accept different appearance of equipment than preferred. 

So much has been made in this community about "snake oil," in regard to cables, and yet the pre/amplification sector puts completely unnecessary meters on gear as though it's important. It's a sales gimmick, a nice thing to look at and feel as though the product is performing oh, so fantastically. It works, as amps with meters sell well. 

I have found no correlation between a product having any particular meter and it's having superior sound quality. The audiophile needs to be sensible enough to accept that they may actually be purchasing a lesser performing component in favor of the appearance. A reputation for attractiveness does little to make a component actually perform in a superior fashion. 

Now, if that discussion does nothing to make you pause and consider, then stop the banter and go buy it. Just beware, the blue meters do nothing to make it a better or worse amp. They are eye candy to sell them. If you can't live without a sense of importance associated with the meters, then buy it - and hope you can get the sound you want out of it.