Hey all,
This thread caught my attention and I have done a little looking around.
The only fully open book I can find is the business ledger; Object Window> *All> Filter> 'TGRFOBusinessLedger'.
I have done some playing about with the ledger but only had a short time to do so - not able to do much but place the ledger.
It seems the ledger object is a fully open book and we cannot 'map' another book model to the ledger.

Maybe one of you has time to check out 'TGRFOBusinessLedger' and see if it can be used to solve the open book issue.
I have to go out now - so it could be a while before I can do any further checking.