The Kohler Rialto is 25 1/4 and advertised as the smallest toilet front to back, but I have never seen anyone say anything good about that particular toilet. I would go for the Toto

Here is a link that might be useful: Kohler Rialto Specs

The Kohler Purist Hatbox is 24-5/8" plus at least 3/4" from the wall. If your remodeling, Caroma has a Wall-Hung toilet which the tank can fit in a 2 x 4 stud wall. It is dual flush to save water. It is only 24-3/8" from the wall. The St. Thomas Marathon II Round, Decathalon Round, & San Remo Round all measure 26-1/4" add 1/2" which is the spacing from the wall.

Here is a link that might be useful: Caroma's web site

I went with a high tank toilet for our powder room at 26.5 projection (that's adjustable). The tank's high up in the air so it "feels" less crowded than many. (That hatbox was a hot second for me when I was choosing). The price on this high tank is hard to beat!

Here is a link that might be useful: high tank toilet

I have an OLD one w/ a flushometer that's probably 18"--it has a side inlet for the water, which makes the big difference. There's almost nothing behind the bowl itself.

I'm scared of ever trying to remodel, bcs we're going to have our noses touching the far wall; it's a narrow bathroom.

(and I like that I can simply lean back on the wall when I'm sitting there)

I wonder if it would be hard to convert that high-tank to a flushometer.... The high tank just feels sort of "looming."

I keep thinking that a company like Kohler could make a MINT by designing a toilet that doesn't stick out so far, that has a tank on the sides, or something.

Someone makes one that has a tank you mount between the studs in your bathroom wall. I honestly don't remember who because it looked too modern for me so I skipped right by it.

rats--I have no studs in the bathroom wall (weird 1921 brick-and-plaster construction).

The Rialto is a tad too modern for me, too.