One Google Maps Key for multiple developers (Android)? Eclipse custom keystore?

Rather than trying to point Eclipse to a different keystore, just replace your local debug.keystore with the shared copy.

In year 2013 for V2 you can include as many keystores app as you like. For me it was debug and production keystores. Just follow process described here (this is a common process). When you create Android Key in Google API Console specify each fingerprint;package.name per line. E.g.:

BB:0D:AC:74:D3:21:E1:43:67:71:9B:62:91:AF:A1:66:6E:44:5D:75;com.example
94:66:06:01:12:27:AC:39:BB:44:90:41:40:86:88:3D:96:A7:99:A9;com.example

That's it! Now you have 1 API Key for 2 keystores.