There isn't one as far as I know.. Unless it's hidden somewhere. They used to have one back when the site was avast 4.8. Not sure why they ditched it... I agree with you, It was nice to know if you had the latest program / virus definition updates by double-checking the site if need be.
Since it there were a few occasions the update process reaches people later than others, but if you knew it was out you could force update it to the most recent one.