Interesting... Sennheiser has some really nice sounding capsules. Would like to learn more.
The Sennheiser K6 microphone series and the newer Senn Ambisonic mic, are based on the KE14 capsule. This is a 14mm electret capsule, gold diaphragm. Very well manufactured, and found in a number of products. I believe some newer mics like e914 and others may have this capsule as well.
The ME64 capsules themselves are available approx $150-200 street price. The bodies for these microphones, K6 series, will add to the price though, $300-400 each total. All of these are available on Ebay in various configurations, cardioid, and shotgun form.
I've often wondered about chopping the ME64 capsule down and running the capsules alone with a battery box. A simple battery box would be sufficient, don't need the bodies/ preamps stuffed in a new box like the other poster built. If a pair ever came up cheap on TS.com or Ebay I would still give this a try.
I never did learn, still hacking gear after all this time, lol.
Richard