As someone who is an experienced tuner and tunes drums to notes, I was curious as to what general notes each drum in Bonham's kit was tuned to. I have a 1970 Bonham kit identical to his (see below), so I wanted to try to tune it as close as I could to his actual tuning. My only resource, other than trying to cop the notes off of records (very difficult and probably not accurate), was the Jeff Ocheltree video on the Bonham kit here on Drummerworld and Youtube. If you go to the Jeff Ocheltree video on the tuning of Bonham's drums, at one point he goes around each drum and strikes the top and bottom heads with a mallet. If you listen closely you can hear very clearly what note the heads are tuned to. Also, when his friend Mark Romans plays the kit, you can get a good idea of what notes the toms are tuned to as well. As he says in the video, the heads are tuned alot higher than you would think. After hearing the notes on his kit, I tried that same tuning on my kit and found that this type of tuning is dead on in the high mid sweet spot of the drums and they sound phenomenal, big and powerful, the perfect amount of sustain and resonance, and with an eerie similarity to Bonham's sound. When I play "Four sticks" on the kit, I swear it sounds just like it! I am assuming that because my drums are the same as far as age and construction (clear maple interior, 3 ply with re-rings) the fundamental tone of the drums is similar and allowed me to tune the drums to those notes. I'm not sure if you could tune another kit with a different shell thickness and construction and get the same results.
Anyway, here are the notes that I came up with from the video. It is interesting to note that the drums are tuned in fourths, with the bottom head being about a third higher in pitch than the top head. 14" tom, top head A#, bottom head C#, 16" tom, top head F, bottom head A, 18" tom, top head C, bottom head E. The bass drum seems to be tuned to an F# on the batter and an A on the front head. The snare drum seems to be an A on top and a G on the bottom, with the bottom head being very tight.