This is complemention for wishment for desktop pure engine launcher. This feature would be handy in session managers, when script already exists, to start it without unwanted gui overhead (gui is run only sometimes, when more instruments are needed).
*** Bug 133 has been marked as a duplicate of this bug. ***
There is now --exec-after-init command line switch, which calls the given command after the sampler initialized completely (see "man linuxsampler"). So this argument may be used for automatically loading an LSCP script as described by you.
For that reason I'm going to close this report.