Contrary to rumors and published reports, the new store that Apple (AAPL) wants to build in New York City’s Grand Central Terminal would not be its largest. At roughly 23,000 square feet, it would be smaller than London’s Regent Street (25,000 sq. ft.) and the Covent Garden (24,600) stores.

But according to ifoAppleStore‘s Gary Allen, it would be one of its least expensive. Restrictions imposed by the landmark building (guidelines here) mean that Apple’s alterations would necessarily be minimal.

Working with details given to the
Wall Street Journal
 by the Metropolitan Transportation Authority, Allen figures Apple will pay

• $5 million to Metrazur Restaurant to buy out the remaining 8 years of its lease for the 9,685 sq. ft. it currently occupies on the east balcony, or $64 per sq. ft. per year.
• $1.1 million per year to the MTA to rent that space and another 14,000 sq. ft. on the northeast balcony, or $48 per sq. ft.

That’s considerably less that the $2,000 per sq. ft. tenants pay in Manhattan’s upscale shopping districts.

Of course, retail space in suburban malls can be had for less than $20 per sq. ft., but Grand Central Terminal is not your typical suburban mall. Some 750,000 people pass through its marble halls every day, and traffic swells to more than 1 million per day during the holidays. According to the Grand Central Terminal website, 50% of its commuters’ household incomes are over $100,000, and 20% are over $200,000.

“Our four stores in Manhattan are incredibly popular with customers and we are excited to bring the Apple retail experience to this incredible location,” Apple spokesman Nick Leahy told CNN.com.

If Apple’s proposal is approved by the MTA board Wednesday, as expected, and construction goes according to plan, the new store could be open for business by November, just in time for that well-heeled holiday traffic.

Below: Renderings of the store that the Wall Street Journal attributed to Rob Bennet for the Journal, but which Allen says were produced by Apple for the MTA.