This is the idea I wanted to try for some time, but didn't yet get around to actually doing it. I have 8100 sitting at home and I use 1100 regularly in my PC... I would make sure to set the output of 1101 to processing without limiting, bypassing the look-ahead limiter. Also bypass the compressor in 8100 going straight into 8100's clippers, as stha points out. I'm not sure off the top of my head wheather compressor bypass will bypass the HF limiter in 8100 as well, but you will definitely want that HF limiter active. I would expect most problems with pre-emphasis as it will be applied after the 1101's MB compressor/limiter and ahead of 8100's clipper. You will have to negotiate multiband thresholds in 1101 carefully as well as the balance between 1101/8100 and also leverage the HF limiter in the 8100. I'm not sure how much loudness (without nasty artifacts) you will be able to achieve overall. Let us know!
If the compressor bypass control bypasses HF limiter as well, you may want to arrange the gain structure (low input drive to 8100 then compensate with clipper drive) as well as set the fastest release time in 8100 to minimize compressor intervention. You may also set the appropriate jumpers in the 8100 for XT2 operation, which would "desensitize" the compressor. If you're comfortable with schematics and electronics, the best would be to apply the compressor bypass, then find the trace that applies the bypass bias to HF limiter and cut it (this is all under assumption that compressor bypass switch removes HF limiter as well).
Regards,
Goran Tomas