My initial reply was going to just be a mention of the cover on XTC's debut album "White Music", but instead, this would be a good starting point.
You might also want to consider going to an online store like CDNow and searching for 'All Along The Watchtower' as the song title.
AllMusic.com lists 130 releases of the song. Click here for that list.
"All recorded versions"? Hope you like The Grateful Dead (played it about 124 times live), the Dave Matthews Band (probably a couple hundred times), Phish (twice), Widespread Panic (7 times), etc. etc. My point being that all or most of those versions were "recorded" and exist in some format or another.
Gentlemen, Heartfelt thanks to all for your input. The project will have to be limited to artists for the first edition. A few will get multiple entries when the performance demands it. Still, perhaps some day when my only concerns are sitting on the porch in my rocking chair, kicking my old yellow dog, I'll be able assemble all the versions. Again, thank you. Jerrod, you are a God. I regard such time and effort a gift, it will be remembered. In addition, anyone who quotes Bill automatically has permission to call me at 3 a.m. for bail and a ride.
"I've read the Bible, and no where in it did I see the words "bunny" or "chocolate". - Bill Hicks