Being able to have the guest OS present shared folders on the desktop, not just when a user is logged into guest OS. Would probably require a 'service' under XP/Vista. Different Mac users could then have a system wide share and a user specific share. Haven't check 5600 yet, but also an option to 'reshare' folders onto mac desktop. Often the shares will get closed/unmounted due to some weird combination of network/cpu/security issues.
When Virtual Machine is started all users can get access to Windows drive by following link /private/tmp/xxxx (xxxx is some number), you can create link on each user desktop and assign permissions Also you can use Parallels Mounter, right click hdd file open with - Parallels Mounter, but users should be logged I cannot clearly understand the last problem.