Draperies. Drape(s) is a verb.
The money seems good until you figure out that anything they didn't buy at Penneys will cost about a grand per window to replace. You shrink them and don't have a pleater to fix them, you'll replace them. Consider also that people are ten times more picky about their furniture cleaning than their carpet, and are ten times more finicky about their draperies than their furniture.
Dry cleaning should be done in a drapery cleaning (not a drycleaners) plant. An acceptable improvement can be had using a dry steam method, and washable draperies can be wet cleaned. If you're already a top-line upholstery cleaner this might be a good add-on, otherwise you'll never clean enough to get good at it.
If you want to be an asset to the designers you work with, find out who the best drapery cleaner in town is and work with them.
PS: The designers might just want someone to do the work at a fraction of what they know it should cost so they can make the maximum profit when they mark it up to the homeowner.