Philadelphia Real Estate blog snapped a picture of a rendering of a(nother) proposal for 1919 Market Street. Numerous proposals for this site have been floated since the lot was cleared for a twin tower to the Blue Cross Blue Shield building next door.
It's not incredibly exciting, and given the number of proposals for this site, I know better than to get excited about a rendering. Still, the porn palaces have been demolished and the number of residents on West Market continues to grow. This might be the most realistic proposal for 1919 we've seen.
Of all the renderings I've seen for 1919 Market, the most architecturally interesting comes from a blog called RICHVILLAMODERN. I can't find much on the site's owner or the artist who drafted the rendering. The design is simply called "New Office Building," a forty story office tower that would preserve much of the lot as a park and public plaza while seven stories hug 19th Street, with the bulk of the tower hovering above.
Likely conceptual, the somewhat Brutalist office tower reflects the philosophy of New York's Seagram Building. After height restricts required New York's high rises to employ setbacks in their design to reduce shadows, Mies van der Rohe chose to circumvent the restrictions by refusing to maximize the space of the lot and set his skyscraper behind a plaza rather than on the sidewalk itself.