copying accounts and transactions from one book to another

[gnucash.133518b at telus.net]

Having duly noted the section B.3.2 Q&A in the guide that says it isn't 
possible to merge two GnuCash files, I have to pose my question anyway. 
I'm experimenting with investment accounts and do not want to do this in 
our working book. Only if the result of my experiments is satisfactory 
would I like to import the investments book accounts and their 
transactions into our working book. There will be no duplicate entries 
between the two books. Is there any way to achieve this without 
reentering the myriad investment transactions a second time? It's hard 
to understand why such functionality is missing from GnuCash, but I 
don't mind having to use indirect steps to meet the goal.

I've seen references to the GnuCashToQIF project, but a read of its web 
page seems to indicate a very incomplete effort that doesn't work for 
investments:

   http://gnucashtoqif.sourceforge.net/

Carl