Interacting with a server on which the darcs executable is not named darcs (but,
say darcs-2.0.2 or whatever) is painful. Some ideas to relieve the pain:

Commands interacting with a remote darcs executable should accept a
--remote-darcs=COMMAND flag. When they are invoked with this flag, they exec
COMMAND instead of darcs on the remote host.

Symetrically, there could be a local_darcs pref telling remote darcs to use a
given command instead of 'darcs' when trying to invoke darcs ot that host.

Duplicate of issue223, discussion there.