A brakes head scratcher (E30 318is)

I have been having a problem with my front brakes vibrating under braking for some time now.  They also seem to rub at a specific point on each side of the car.  I have noticed this recently by applying the brakes lightly whilst rolling down a hill.

So far I have changed the pads, discs, checked the bushes, the bearings, the steering alignment and the track rod ends and I have even changed the seals and guide pin bushes in the calipers, but the problem still persists!  I changed the seals at the weekend and since then the vibration has been amplified.

The only possible answer/solution my father and I have come up with is to chamfer the leading edge of the brake pads, in case they are catching and causing judder, or that the disc is not seated properly on the hub, is slightly off alignment, causing it to wobble as it goes through the caliper.

If anyone has some words of wisdom I would be more than interested in hearing what you have to say!!  I can't bear the thought of being beaten by this, having to take it to a garage and for it to be something realy simple to fix.

The handling of the car is perfect, no wobble/vibrations when driving under normal conditions.  The wheels are standard and I have rotated them to make sure it wasn't the tyres.  Its only under braking that I feel the vibration through the steering.  I'll double check on the way home to see if I'm getting any vibrations through the pedal, but I don't rember any.

Right, I drove the car and paid special attention to the vibrations I was/the car was experiencing.  There is no discernable vibration comming through the pedal but there is some coming through the steering wheel.  This is amplified intermittantley whilst braking in corners.

In responce to Brucey's comments, I have done a visula check on the bushes and they seem to be good.  I sanded the brake pads when I refitted them and used parafin to remove any grease/brake fluid from the disc brakes.  Ive also rotated the wheels to check for inbalance or faulty tyres (buldges).

The thing that get s me is the irregularity of the vibrations.  Sometime they are quite violent and sometimes you hardly feel them.  Its very hard to take note of all the factors when the vibration is violent, but the information above is as accurate as possible.  There is no wobble in the steering when driving normaly, the car seems to drive fine, so I'm 'steering' away from the idea that it might be the bushes, but I'm happy to be proved wrong if someone has a theory!

-you have GOT to get your wheels balanced properly if you have not done this already.

-your wheels weighs 15 to 20 kg each; if they are even 0.1mm off balance driving the car will be like driving a road drill....

-take your wheels down to a reputable tyre fitters and get them balanced if there is any doubt. They can look just fine, round etc but still be well off-balance.

I thought I had found the culprit last night.  The driver's side track rod end had a break in the seal, so I whipped it out and put in a new one.  This morning, the tracking was slightly out, which I'll get sorted today, but I can still feel vibration, although it is dramatically less than before.  Going round corners as well, causes much less vibration then before. 

So, could there have been some uneven wear on the discs as a result of the worn out track rod end??  The brakes still catch slightly when the car is creeping forward down a hill and the brakes are lightly applied.  Its like there is a high spot which rubs against the pads once every revolution.

Thanks for your help!!