NO! You cannot have more than 4 virtual drives, and this will never ever be changed. If you want such feature, wait for Daemon Tools Pro, buy alcohol 120% or some other commercial software. Daemon-Tools is free for personal use, so don't complain!

You can also check out some 3rd party tools, from the main page. Some of these are alternative front-ends, and quick mounting tools, which let you mount images more easily and quickly.