Any tips for getting near to isolating the dialogue elements from a film soundmix?

I'm trying the impossible (I know what Yoda would say to that).

I know that there is no scoreless and sound effect free isolated dialogue tracks for the Star Wars films (other than what's sitting in the Lucasfilm vaults).

But I am attempting to edit the audio of a scene as close to scoreless and effects free as possible and I would really welcome any tips as it is a labour of Heracles.

I'm trying to construct a rough cut of the council scene from TPM with a mixture of dialogue from other scenes.

My first attempts flow quite well (for rough cuts).

I've attempted to strip away some of the intrusive elements via a mixture Audacity and Garage band filters but the results sound a bit like a telephone call down a long tube and even then I still get the odd blob of persistant LSO complaining in the background.

Help OT.COM boffins, you're my only hope. 

I'll have a go with the gate types on the programs I already have first, thanks for the pointer Satanika.

vbangle, I followed that thread (largely because I knew I would be attempting this mini project) so I wasn't ever convinced, it's never a good idea to make wild claims unless you can back them up with extraordinary results.

Still the kid at school who told us he was Superman really could fly (for a few seconds when we craned our necks 90 degrees).

Made any progress Bingowings? Being able to minimise the music would make my edit one hell of a lot easier.

As I posted on the other thread I've had limited success by going back and working on it from a word to word basis (which is very very time consuming).

There will be instances where it may be necessary to go further and break into longer words and strip the sounds at either end and then apply a gate to the remaining sound componants and then reassemble them (and even then it will not be perfection).

If we has a team of people with no friends and no social life who could do this for each character we might get a workable dialogue bank by 2017, it really is a labour intensive job with no quick fix solution that I can see (other than breaking into Fort Skywalker and liberating the data tapes).

Are there any key scenes you need attempting?

Pretty much every scene in the film is being rearranged, so the music won't match up when there's a cut.

What do most editers do about this? Add sound fades to make it less jarring?