If you would have only one Scanner the Canon CanoScan 8800F would be a good choice. But that is a A4 flatbed Scanner.
The only other solution is to use two scanners:
- Reflecta RPS 7200 or ProScan 7200 for the Negative
- Reflecta DigitDia 5000 for the slides (but this one is nearly as big as a flatbed scanner).
But the 3mm slides could be a problem with the DigitDia - so I suggest to try this before you buy. (with the 8800F this is no problem).
For that amount of negative and slides you need a scanner which allows to scan them automatic or like the 8800F a few in one process. (8800F up to 12 negative or 4 slides).
To use a scanner which can only handle one negative or slide will be frustrating after about 100 scans.
I think there is no slides scanner who can do that which is much smaller than A4.
You will find some scanner test from me on my website
http://www.jostark.de - but all in German.