Yes, line locks are commonly available from ANY speed shop.
Transbrakes for the 200-4R are now plentiful when you deal with TR-specific vendors. The cheapest and easiest-to-install option is the Stage-Right trannybrake ($120). However this is like revving the motor and doing a granny-drop. There are also a few electrically controlled units available from PTS, Extreme Automatics and CDK Performance...(not sure if I have the last name correct.) They are a few hundred dollars more, require professional installation and often require a deep tranny pan (more money).