Flaser, did you even READ what I said carefully? I didn't say REAL rockets have constant speed = constant thrust, I said that in FS it SEEMS so. I gave a _possible_ explanation for why the trails would only get larger with speed (that the trails may not actually be thrust, but just emissions).
I also gave a reason why it _could_ be done this way: it's easier on the coders and is pseudosciency enough that most people would buy it. In fact, it would make sense to most of the "normal" people.
Hence, greater current speed = longer trail is a feasible idea that need not be impossible (even with "realistic" physics). And with the advent of the possibility of bending trails, it won't _look_ ridiculous (i.e. pretty, but fairly ridiculous).
An ion rocket works exactly like an ordinary rocket except it spews out ions instead of normal atoms, so it can use magnetic fields to steer the substance thereby enabling the usage of higher temperature that would melt any ordinary nozzle made of the best materials you can come up with, higher temperatures means faster exhaust gases - ergo greater thrust.
Actually, what you've described is a plasma rocket. High temperature ionized gases = plasma.
RL(tm) ion engines neither produce a lot of thrust nor do they use super high temperatures. An electric field is used to focus and accelerate ions that serve as thrust. In fact the key feature of ion engines is fuel economy. They may not have a lot of thrust, but they can produce continuous thrust for a very long period of time.
