ASD with stand option is about $2K. There's no Mac in there and no keyboard + mouse. New iMac is not going to be at refurb or year old discount prices, so the math must work from MSRP for new.
I think iMac "Bigger" will be branded PRO and come with PRO & MAX SOC options. So the minimal spec will be the M3 or M4 PRO by the time it hits. How much does minimum spec Mac Mini PRO cost right now? $1300.
$2000 + $1300 + Keyboard + Mouse = a probable "starting at..." of $3499 if it was available today. Give it a little inflation bump in the next year or two, spin some "supply chain issues" and maybe that becomes $3699-$3999?
Does that seem plausible? How much was a much older iMac 27" Pro "starting at..."? $4999. It's not hard to imagine Apple being on stage comparing the new iMac Pro to the old iMac Pro and how nearly ever part of it is superior to the old one (which of course it is given the age)... then making it seem like $1,000 less is an incredible bargain.
Now, if it goes as today's rumor suggests and it's going to grow 4 inches and use the Pro Monitor XDR screen and presumably resolution, then I would work the same basic math from its $5K monitor-only price (or maybe $6K with monitor stand). Starting at about $6500-$7500... and add $1000 for that magical stand.
I think all the concepts of a new iMac "bigger" priced like the one we remember are impossible given the price acceptance of ASD for the very same display by itself. The pricing to add a Mac to that would have to work UP from ASD new.
That kind of pricing would also not undermine the separates pricing of pairing Mac Mini or Mac Studio with ASD or Pro Display vs. a super bargain AIO which would make both of those lines much harder to choose if one needs a monitor too.
And it would be VERY PROFITABLE for Apple, likely bringing an iMac Bigger into their target margin range... which is actually why I think the 27" was temporarily killed (it no longer could generate enough profit at traditional pricing).
The ONLY way I can imagine it starting much below about $3500 is if it is NOT branded PRO, uses the base chip, probably is only 27" (which seems shaky since 21" became 24") and specs are kept minimum to hit a low price. But even with that, it's hard to tabulate much below about $2699 and my low, low "starting at..." guess is likely more towards $2999 with specs so low that most would want to pay up for some upgrades. Add a little more RAM and a little more SSD and it's right back to $3500-$4500 again.