Some form of app that 'hacks' into LFS and adjusts the speed variable's value externally through the appropriatly accessed address would be the solution.
However DO NOT EVEN TRY IT. If u figure out how to do this - it also means you figured out how to create a dreaded speed hack.
An external application that can control a car's spead in any way is generally something that is not legal here.
So the answer is - no. Because it will get alot of people possibly banned.
EDIT: this does not apply to servers with CPW turned off , as in Servers that allow Modified ( as in directly modified ) LFS.EXE files. However - and external hack app would likely still be a bad idea even in that scenario.
1: It's not 'Cruise Control' - it's a speed limiter on some cars to prevent violation of pitlane speed - and is a safety feature.
Cruise Control allows you to change your speed when u feel like it at any time.
A speed limitor does not.
2: I'm sure a demo user has experianced speed limitors in the pits.
Cruise Control in a pitlane would not be considered cheating - it is pure lazyness. It isn't hard to control your speed in the pitlane if u have a pedal.