Marc,
If running on manual with film gets you the shots you need, there is no reason you can't do the same with a high end digital SLR. When I machine gun anything, I run the digital cameras on fully manual as appropriate, and I get consistent excellent results.
Turn off the AF and run manual if you are having problems with it. There is a learning curve with AF since the sensors are not exactly where they show on the viewfinder. Thus, once you understand where they are, and how best to use them, you can get very consistent results with it. If you are not aware of the actual placement, it can run haywire on you. But luckily, there is manual focus!!
You can pre-set the auto white balance to whatever file type you would normally use (ie, daylight, tungsten, etc) If the conditions change on you, use a color correction filter just as you would on the film camera. Once you preset the color balance, it is extremely consistent. Its neat that you can look into the files and see the actual numerical values, as it does show the consistency in pre-set modes. I've never had a problem with inconsistent white balance on the S2, S1, D1x, or D100. I haven't really noticed on the consumer cameras, since I never looked closely. The S2 cameras get high praise from the wedding photographers who are deadly concerned with white balance and color casts due to the brides white dress. And they shoot in event situations with varied and mixed lighting.
If you are getting exposure errors, turn off AE. However, I've found the Nikon matrix meter to be so good, I use it all the time. However, I am acutely aware of whats going to fool the meter, and under those circumstances I adjust it as needed. But 95% of the time, I find it doing exactly what I would do manually, so I don't mind delegating that task at all, so I can concentrate on my subject and composition.
You use top level digital SLRs, so they are all able to run under complete manual control. You might want to try that, just as you would with your manual cameras. Then any issues will be you, and not the camera, and thats easier to fix than the other way around. Once the digital camera is under manual focus, manual exposure, manual color correction, etc, the sensor will act just like a piece of film would, and I can not understand how you wouldn't get consistently excellent results because you have completely eliminated all the issues you brought up.
But I also have a hard time thinking the digital camera is the problem since the majority of amateurs I've met are getting consistently better results than they ever did with film cameras. And they don't know photography. They don't know how to read a scene. They just point and shoot, and get nicely exposed images, balanced flash, etc. Even my mother improved 500% when se got a digital consumer camera. And they suck compared to a prof SLR.
If the opposite is happening, there is something wrong! Especially if you are using top quality digitals. I don't know of one professional I work with that has the issues you are running into. They all praise the speed, consistency, and accuracy of the top end stuff, and are delighted that most images need no post processing at all. The pros are changing in droves to digital, so I find it hard to believe such a picky bunch of people are moving in that direction if their consistency and results are diminished. Its their lively hood, and if they weren't getting better results, they wouldn't be going digital
Check out my Photo.net gallery.
http://www.photo.net/photodb/member-photos?user_id=584167&include=all
90% of the images are digital. Few were processed other than to resize and compress for the web. A few were sharpened or levels adjusted, but most are direct from the camera, resized, compressed, and uploaded. Most of the stuff I do post process are B&Ws for conversion, toning, dodging and burning, and artistic reasons.