Someone mentioned Physical Graffiti, which I agree does definitely have an awesome bass presence. Thing is, mixing procedures were different i the 70's. Guitars were a lot thinner, and probably double tracked most, if at all. Any organ/key sections in those Zeppelin songs were also a lot more minimal than the stacked patches that JR uses. In other words, there was a LOT more room for the bass.
Also, rock music from the 70's was all about the groove, and the fundamentals. The bass and drums were a lot more critical in filling out a mix.
Whenever you have a band like DT who relies on such a huge sound, it can be difficult to accentuate the bass. Bass hogs up a mix in a way that no other instrument does, so if you want to make the audible EQ range of the bass more up-front, you'll have to sacrifice that of the guitar, strings, piano, vocals, and all other sounds which contain information in that EQ range.
All of that said, it is definitely possible to lend more sonic space to JM. DT has done so in the past. But it is not as simple as turning him up, as every other instrument would need to be notched out to do so.