In two builds now I've seen that Windows 7 creates a small partition of 200 MB or 500 MB to house the system files, bootmgr and the folder Boot. Even if one selects Disk 0 Partition 1 to install on, the small partition is first created before installation starts. Here's a screenshot from Windows 7 and another from Windows XP on the same system. Interesting that Windows XP placed it's boot system files (ntldr, NTDETECT.COM and boot.ini) in the little partition too.
I still need to figure what the implications are for dual booting, but it wasn't too much of mission to get XP installed and a dual boot functional with Windows 7 installed first. Oh yeah, there was no drive letter allocated to the small partition, so I allocated the first offered, thinking that would be necessary for XP to be able recognize it.
Disk 0 and Disk 1 as per the XP screenshot, were added to the system after installing Windows 7, so at the time of installation Windows 7 was installed on what showed up as Disk 0.



