i have a "workaround"
you may have heard that you can add a kernel loader to the windows nt bootmenu? its relatively easy there are step by step guides just google it.
all you need to do, is write two different boot.ini files, and have a script that does attrib -h -s -r boot.ini & ren boot.ini boot.other & copy boot.linux boot.ini & shutdown -r -t 00 and it will shutdown windows and boot linux. all you need to do is write a script under linux to do the same thing, or if you run wine with the appropriate permissions you could even run the same script under linux before you reboot.... thats what i would do if my scond box had no monitor.
It would at least give you the functionality you want, i.e decide what os will boot (next) , via vnc.
