If by "screen fill" you mean expansion of non-anamorphic letterbox dvds to fill a widescreen tv from side to side, yes. This is more commonly known as "scaling" for non-anamorphic widescreen dvds. It's automatic but dependent on flagging on the disc and not all discs are flagged properly. You select "16/9 Normal" under TV-Type in the setup menu to enable the auto-scaling feature. There's also a "16/9 Auto" selection which disables the auto-scaling. This is counterintuitive imho.
It will also put black bars on the sides of 1:33 aspect ratio movies like Citizen Kane for a widescreen set left in "full" mode, so you won't have to use the gray bar mode on the tv.
The JVC players do a good job on film based material as far as the de-interlacing goes, but fall behind the Sage-Faroudja deinterlacer models with video based material. They also do not have the chroma bug.
To the best of my knowledge nobody makes a player with the Sage Faroudja chip, no chroma bug, and scaling.
Joking aside, once you get them used to widescreen, they won't wanna go back. My wife (who didn't even have a DVD player at her disposal until we started dating) was just commenting this weekend on how badly X-Men was chopped up when they were showing it on FX. She couldn't stand watching it, and just had me put in the DVD. This is a woman who had never watched anything in OAR outside of a movie theater 2 years ago. Most folks here aren't likely to try and help you out too much if your goal is to zoom out the black bars.
The black bars are your friend! Love them...cherish them!