Not really a script, but I think it cann easely be done with the command mminfo.
Something like:
$ mminfo -X -q 'savetime>yesterday,savetime<today'
Tis will give a summary report of all data backed up yesterday.
Note: If you don't use a time, it will use 00:00:00 as time in the query. So 'today' means 'today 00h00m00s'