Thank you for this post. Upselling is an essential component to business strategy. You bring up a great point about inventory that simply doesn't move. What I do with this, is find a local business which employees a high rate of your ideal client profile. package this product in a creative way which invites them to your business. This of course works best for lesser value products. If you are going to take a hit, doing so for a new customer isn't a bad trade off.
I think the real kicker when it comes to cross/upselling is the ownership and management are often on board, but the staff are not. Educating staff on the HOW and WHY to upsell is critical to a successful upsell strategy.