There are Fry’s on the east coast. Atlanta has one (maybe 2 now) I guess they haven’t meandered up to New Jersey yet. Radioshack does typically suck for enclosures.
Really, putting the connector on the 6x1 side doesn’t sound too hot; putting it on the 6x3 side would put the center of gravity closest to the connector.
digikey.com
click Go
click Boxes (3,312 items) (under the Boxes, Enclosures, Racks category)
Use Control-Click or shift click to select all of the Plastic materials (I’m assuming you dont want metal)
Check the box for 'in stock’
Click ‘Apply Filters’
Then start looking through the Size/Dimension for something that will fit.
There’s a 5.99x3.24x1.38, or 6.18x3.7x1.42, or 6.1x4.6x1.37, or…
there’s also Mouser.com, with over 6,000 enclosures, like maybe 5.9x3.15x1.18, or…
Tons out there, and that’s only two places to look.