>The days of wired keyboard and mice are mostly over, even for desktops<
You'll have a tough time making a case for that one. I'll agree that everybody tries them on a desktop at some point, and hence the market for them. Afterward, they realize they've traded a wire mess for a battery mess, so the keyboard and mouse go into storage for 6 years, and then move to recycle. To add devices to the dongle requires installing proprietary software, and since when are desktops short of USB ports? They have them in front, back, and half the time on the monitor.
>Of course, the draw of the nano receiver are strongest for the laptop market<
Only if the laptop doesn't have Bluetooth. When it comes to mobile devices, who is going to try to sell a cell phone, or tablet without Bluetooth? You add it to your laptop because it's the most convenient way to sync apps, transfer files, and use a wireless headset. If you plug in USB, it's because you want to charge the battery or move a lot of data. If Unify had come out 10 years ago, before Bluetooth had its act together, smart phones weren't smart, and tablets didn't exist, it may have been today's Bluetooth. Bluetooth still has a place only because it requires far less power the Wi-Fi. If Logitech wants to get attention and boast about a first in the market, make it that all of their wireless devices use the standard Bluetooth protocol. They can't go wrong with that one. (BTW, I'm not a Bluetooth fan. This is simply reality.)
A nano dongle left in your laptop sounds better than it works. I have a nano dongle on my Microsoft 4000 laptop mouse. It's a WONDERFUL mouse. The diminutive size of nano dongle sounds good until you actually try leaving it plugged into your laptop. It snags going in and out of the laptop bag, and you're always in fear of bumping that side because any impact will be on the dongle, and the risk is to your motherboard. I'm an IT consultant which means my laptop is going places all the time. Realistically, my options are: live with the stress associated with leaving the dongle plugged in, remove the dongle every time I go somewhere, or ditch the dongle. The only equipment that uses the dongle is the computer, and Bluetooth can be more easily integrated into them than anything else. Phones and tablets are everywhere, laptops are getting thinner and smaller, and every OS ships with a Bluetooth stack. If I were going to forecast anything's imminent demise it would be the dongle. Unify is a cool idea, but it's like an improvement for horseshoes.