They’re still building in Cielo, and there’s still a lot going on over in The Bridges (even though that place technically has its own Zip). The Crosby, which is located directly across the intersection from Cielo (albeit in 92127’s zip) is also going string, although those homes are mostly production homes, not customs. Then of course, there’s Santaluz, about 1/3 of which are customs. Then there are all the wannabe projects in the Del Mar Heights area (Rancho Del Mar, The Preserve, Duck Pond, Meadows Del Mar), as well as Wildflower in Olivenhain.
There are no shortage of McMansions in North Central. And most of them have easier access to the I-5 corridor. Cielo seems to be more proximate to the I-15 corridor.