Decorating non-fabric items is something that can be done without special sublimation inks and printers, and without the need for a polyester-coated surface. All you need is a laser printer and special hard surface paper, along with a heat and pressure source. By using laser hard-surface transfer paper, you can decorate just about anything. Head to your local dollar store or craft store and browse the aisles for items you can customize. This quickly makes that $1 for one item a $10 item, and you are not limited to white or light surfaces.
Think about putting white letters on acrylic awards. How awesome will that look? These items may not be quite as durable as sublimated items but add a little clear polyurethane coating or other protective top coating, and you can have a durable piece.
The upfront investment is greater, but the long-term return on that investment does look promising due to the new range of products you can offer, and the higher profit margin you can get for dark garments and hard goods.