And yes, you are right. Developing something like this is going to take some time. But I do believe that the developers will be able to implement this within a reasonable time period.
However, as I said, the actual storage/update/query of data should not be monetarily expensive. Given my observations (and guess), it will probably make 1 query every couple seconds across entire Tower Unite. 1 qps in tables with 10k record is really light on any database system even with very crappy hardware. I estimate that the cost of running a server instance solely for that purpose will probably cost less than $5/month.