For those of us that loved watch the Thing fight the Hulk, Fantastic Four 112 from 1971, titled "Battle of the Behemoths" was a doozy. After a quick search on ComicArtFans, I see that my love for this particular issue is shared among many geeks.
The original cover to Fantastic Four #112 by John Buscema was simple and effective, showing the two Marvel monsters about to trade blows. It looks to me like this cover was both pencilled and inked by Buscema, or at least, it was not inked by Sinnott. Marvel Wikia also states this as well.
Michael Finn is a great Marvel fan with gallery on ComicArtFans (see links to all sources at the bottom), with tons of commissions. Michael has a series of them titled "One Minute Later" where he gets an artist to interpret what happened one minute after the original cover. In this one, Mike McKone gave his vision and the cover is numbered 112.5. One of the things you can see here about modern Marvel vs classic Marvel: the Hulk is always drawn much bigger than Ben Grimm in the present day, whereas in the past the Hulk was almost the same size as the Thing.
Buscema re-created this cover several times for collectors. The version above was commissioned by Bill Thomson and it's very faithful to the original. One thing I have always wondered about these cover re-creations: how do the artists reproduce the title logos and Marvel sidebar?
Gary Sella also commissioned Buscema for this cover, but with a twist: adding Mr. Fantastic into the middle of the fight!
Ending this with a giant-sized piece of art, here is a look at the original art to the splash page of Fantastic Four #112. I am especially enthralled with the creator credits on the lower right, framed by bullets exploding into the tree the Thing is holding up. Nuff Said!