Jeremy,
I have 17 plug-ins and I de-activated and refreshed the dashboard for each one with the exception of one (BBPress) - which I will test in the wee hours of the morning when there is less traffic.
So far, no hourly stats on the admin tool bar. Will write again to confirm 100% plug-in testing tomorrow morning.
I have some customizations in my functions.php file, to remove the WP logo and the "site name" from the admin bar - but I added that AFTER I already didn't see the hourly stats.
Ciao,
L