It's Sunday so I've had sometime to think about this and I'd say give it a whirl, but set some goals/paramaters. I will only try this for x months or loss x amount.

I'd get creative in how you can generate revenue too besides the demand/customer few. Right now people in the comments are focusing on the scale, well it's a hard product to arbitrage, but

1) Could you sell space on the cups for ads or other start ups? This might be the one time QR codes could work!. A Well placed QR code on the cap??

2) If you try to cut your costs (ie the coffee) look into a starbucks gift registered card, every x number of coffees you buy you get a free one. Also, once you hit a certain threshold you can customize (add flavors) to cups of coffee for free. Still charge the customer for it, but you get it for no additional cost.

3) It doesn't have to be Starbucks. I'd try partnering with unique coffee shops and try cutting a deal with them. They get people aware of their coffee and grow their customer base.

4)Or just simply use this to meet people doing interesting things. Who doesn't have time to get coffee in the morning--people who are doing things. Who can offered to have someone delivery coffee to them? People who've made money doing something.

Best of luck, interested to see what you do with this!