I have a sleeper sofa bought from Macy's in the Boston area in 1998.
It's a medium-light blue, almost a denimy look, with edging on the
pillows in a blue and yellow stripe. At least one of the bottom
cushions' cover has given way. I'd like to get replacement cushion
covers, or replacement cushions. Unfortunately I don't know the brand
name of the sofa. Would appreciate any help locating replacements!

Is this the same style of sofa?

http://www.macys.com/catalog/product/index.ognc?ID=100700&PseudoCat=Search

Although, those are only "slipcovers". I'm not sure if that would be what you need.

This may seem like a silly question, but have you looked thoroughly
for a tag? If you haven't already done so, check the bottom of the
couch and all of the interior, including "cracks" in the upholstery.
If you want a replacement from the original manufacturer, this would
seem to be the only hope.

One problem you may end up with, however, is that the new cushion
fabric will look quite different from the rest of the couch. It will
be from a different dye lot, and dye lots can vary quite a bit. In
addition, the rest of your couch has some wear, which can affect
colors.

kriswrite