Generally you need more than a cable.
This is true if you run a normal condensor mic. The transducer part of it is simply a gold membrane moved by the sound wawes, in front of a backplate. The electrical signal is indeed quite tiny and extremely sensitive to interference and you need the electronics real close to the membrane. This is why we have the active cables - there is at minimum one transistor in the cap end of the cable. This also means that this is possible with some microphones and not with others.
Sometimes you can get away with a very short cable between cap and head amp (the rest of the mic), but it will be quite difficult to make it work.
So if you want smaller mic head, there are other solutions. Ready made systems comes to my mind (say, Schoeps has these lovely capsules and active cables, and a bit of a price). Smaller mics, say DPA 4060 if you want to go really tiny.
// Gunnar