Yesterday afternoon, the day before Halloween, several real-estate agents and their children went on a special trick-or-treating route on the 4100 block of North Bell Avenue in Chicago’s North Center neighborhood. Stopping at five of the six houses that are for sale on the block, the kids picked up treats—but what their parents saw was pretty scary.

On this block alone, there are four new replacement houses in the $1.2-million to $1.4-million price range, all finished (or nearly finished) and unsold. Also listed for sale are an older house priced at $630,000; another replacement house soon to be finished;  and a house that was new less than four years ago. That’s about 20 percent of the homes on the block.

This block, as well as those nearby on Claremont, Oakley, and Leavitt, have seen several waves of new construction over the past several years as builders and buyers discovered the appeal of this sometimes overlooked area that sits between the pricier Roscoe Village, Lake View, Ravenswood Manor, and Lincoln Square neighborhoods. Builders tore down a few dozen older, smallish residences and put up new houses that, following the preference of the local alderman, Gene Schulter, generally mirrored the farmhouse styles and raised front porches that characterize the area’s older housing. Buyers were drawn by the relatively low house prices, the shopping and dining along Lincoln Avenue, and the family-friendly amenities available at Welles Park, a few blocks north.

Joshua Katz, a Rubloff agent with a $1.359-million listing at 4154 North Bell, says the new housing “came in waves as the neighborhood improved and improved.” The new residents, in turn, encouraged further improvements in the neighborhood’s schools, retail offerings, and other resources.

But when the real-estate market slowed to a crawl this summer and fall, some builders were left with houses for sale. That’s the situation on the 4100 block of North Bell. While each builder’s house is distinct from the others on the street—Katz’s listing has a walk-up attic and several energy-saving features, while down the block, Doug Mulderink touts the fully sodded lawn and electrically-controlled skylights in the $1.229 million house he built—they all have one thing in common: the houses are all unsold, and there is a good chance they might sit unsold through the winter.

Mulderink and Katz both profess not to mind (even though Mulderink has a second house on the block nearing completion that he will also price for about $1.229 million). But the last sale on this block was in January, according to the Multiple Listing Service of Northern Illinois, and the highest price on record for the block is $932,000, paid more than two years ago. Sales of more than $1 million in the neighboring blocks are more common, but of the 14 recorded sales in this neighborhood, most occurred in 2006—and the latest was in August 2007.

Katz figures that any of the Bell Street Seven that are still on the market at the end of November will stay put until next spring or summer. Until then, this is not a street for the easily spooked.