Thanks for the links Jim. I can't see a cost there but a bulk deployment makes a lot of sense to me.
The reports from the scientists deploying these things seem to indicate it can take a few days to find an appropriate floe to drill through and place a buoy, and a day or so to set it up and calibrate it. 10 per day doesn't look feasible to me. Think also about how much cargo space each requires, and how many you can actually take with you per trip - the sheer physical logistics of deployment.
As I suggested, the first issue can be avoided if (at least most of) the buoys are dumped in the water near the end of the melt season and the ice allowed to freeze around them. Deploying an average of 10 per day in this way should be doable.
The buoys can be shipped to the Arctic by container ship. A 40' shipping container is either 66 or 78 m^3 (web search returns both numbers) so, depending on the size, each one should hold some tens of buoys ready for deployment. Let's assume 40 buoys per container, so 1000 buoys would require 25 containers. Then that would require picking up and deploying one container worth of buoys every 4 days.
I suspect that a lot of vessels would be available for hire that could deploy them over much of the Arctic Basin during the melt season - it need not require a full ice breaker and could be more than one vessel. Such vessels also could transport the buoys to the ice breaker for deployment from that.
So the numbers still seem reasonable when written out on the back of an envelope. It's probably worth fleshing it out a bit more to see whether there is a show stopper or not.