I'd like to see a website that has the following information about the hotels it lists:

-When hotel was built
-When hotel was renovated
-Square footage of rooms.

Does it exist?

Lots of websites have this information, especially European hotels. I noticed several NYC hotel sites had the square footage of their rooms, as well as sites in Paris. By reading your title, I assumed you wanted links to some of those ultra-fancy dream vacations to exotic places. I'll give you one anyway...http://www.slh.com/index.shtml

No, not looking for ultra fancy at all, just looking for the data.

No single website has that type of info.
Most individual hotel websites don't even list a lot of those specifics.
I often resort to calling the toll free hotel #, where you can get the most specific info.

Most larger hotels include this data in the descriptive information of the property profile in the global distribution systems, used by travel agents AND websites such as travelocity.com
It may take some looking but you should be able to locate it.
Here's the info for the Sheraton Towers in NYC:
II. PROPERTY INFORMATION
PROPERTY TYPE -
LUXURY
*DESCRIPTION-
PROPERTY TYPE - FULL SERVICE - HOTEL
YEAR BUILT - 1961 YEAR REMODELED - 1999
WORLD CLASS SKYSCRAPER HOTEL IN THE HEART OF MIDTOWN
MANHATTAN STEPS FROM BROADWAY AND 5TH AVENUE SHOPPING.
OPPOSITE SHERATON MANHATTAN. OPIOOIND ATHEATRE AND 5TH
AVE SHOPPING.. OPPOSITE SHERATON MANHATTAN.THE 50 FLOOR
HOTEL FEATURES 1,750 GUEST ROOMS AND 2 LEVELS OF
ACCOMMODATIONS TRADITIONAL ROOMS AND CLUB LEVEL SMART
ROOMS. WITH A THREE-DIAMOND AAA RATING THE HOTEL ALSO
INCLUDES 31 SUITES, 206 CLUB LEVEL SMART ROOMS, 3
RESTAURANTS AND LOUNGES AND 55,000 SQUARE FEET OF MEETING SPACE

Here's a sample of the square footage text, it goes on to describe each room type offered:

A -
MAX OCCUPANCY - 3
MAX NBR OF ROLLAWAYS - 1
TRADITIONAL ROOM. APPROX 165 SQ FT. CLASSIC CHERRYWOOD
COMFORTABLE FURNISHINGS CONTEMPORARY DESIGN. IN-ROOM
SAFES - MOVIES/GAMES/VIDEO CHECK-OUT.
NO SMOKING ROOM

ttt

ttt

AAA will give you the first 2 answers. As far as the square footage you have to call the hotels direct or go to their websites.