Reverse entries are just one of those things that is blown way out of proportion by the GT5 kiddies. Mainly because you simply can't do it consistently, so to try to do it a lot in real life would get expensive fast. Thus you don't see it much in the real world. The videos people post of their GT5 reverse entries are usually after hundreds of laps of screwing the pooch over and over. You don't see those laps though, you only see the one time they barely pulled it off.
I mean don't get me wrong, that's cool to set a goal and strive for it and everything, but reverse entries do not automatically make you a badass. In fact, both of the GT5 reverse entries posted in this thread are pretty sad drifts. They both understeer upon approach to the corner. Just because it's reverse entry doesn't make it a good drift, it needs more than that. It needs smoothness and consistency. For example on that LayNLow video, the backwards entry was probably his worst drift in the whole video, yet he made it the focus of the video.
This forum is so shallow sometimes it makes my head hurt.