Egan tells GlobeSt.com he intends to "contact all major user/developers in the office, medical office, hotel and residential segments." The tightening office vacancy, expanding medical facilities and expansion of the Pennsylvania Convention Center make the first three options viable. Regarding residential, he says, "not condos, but rental apartments are in short supply."

Under an office or medical office scenario, he says the project would likely be a build-to-suit, "most likely for a local company that's already Downtown. There are not as many large blocks of office space in Center City as there were a year ago." He says an office user's rent rate would probably be in a range of between $30 per sf and $35 per sf, noting that medical offices would probably command a higher rent rate, depending on build-out.

Neither Zuritsky nor Egan would provide a projected cost of even a shell structure. "Apartment and hotel companies value differently from office users," Egan says, "and the costs for each type of building would vary widely." In a scenario other than office, he says Parkway would likely seek a joint-venture partner.

Parkway, which owns and operates most of the city's parking garages, has several other developments under way here. Among them are the W Hotel & Residences at 12th and Arch streets in which it is partnering with Urban Residential; the 1706 Rittenhouse condominium with Scannapieco Development Corp., and the recently completed Pearl condos in Chinatown.

Despite what many have called a condo glut in Center City, Zuritsky says, 95 units in the 100-unit Pearl at 9th and Arch streets are sold. He acknowledges that they are considerably less pricey than the W and 1706 Rittenhouse condos, but says the 32-story Rittenhouse condo will break ground within a couple of months, and "we've had good activity for residences in W," which is under way at 12th and Arch streets. Speaking of all three projects, he says, "each product is a niche, and all have been extremely well received."