Well, I did the same thing that you did, so I might as well write a guide:
How to Install Windows 7 on a Dell Mini 10v After OS X
This guide is NOT for the faint of heart. If you screw something up, your computer might be bricked. (But you're following my guide, so that shouldn't happen... right?)
1) Back up your existing OS X installation. Time Machine is good, though other backup solutions (preferably bootable ones) might serve you better.
2) Go into Disk Utility (/Applications/Utilities)
3) Click on your hard drive. Go to the Partition tab and create a partition on it (allocate as much space as you want for 7; format it as FAT32)
4) Go onto a Windows computer. I will assume that you are using Windows 7 Home Premium that you purchased from Microsoft's Digital River store, but any ISO of Windows 7 will do.
5) Get a flash drive that is 4 GB or larger and format that as FAT32 (you can use NTFS if you want to, but I found no problems with FAT). Backup any sensitive data on it first.
6) After formatting the USB drive, run Command Prompt as an administrator (right-click on it and select "Run as Administrator." You might be required to input a password).
7) Type in (without the quotes; this goes for all other terminal commands) "diskpart". This will initialize a powerful program that you will need.
8) Type in "list disk". You should see a table with the different disks connected to that computer.
9) Note the number of your USB disk, and type in "select disk X" (where X is the number of your drive)
10) Type in "list partition" and then note the largest partition on the drive (if there is more than one, that is). Type "select partition X" (once again, X is th partition number)
11) Type "active". This will allow the computer to start up from the flash drive (with the help of a later step).
12) Now, minimize Command Prompt and open up the Windows 7 ISO. You can use any virtual disk tool or WinRAR and extract the contents of the ISO to a folder.
13) After mounting the disk or extracting the contents of it, open up Command Prompt and use the cd command to navigate to the contents of the ISO.
14) Type in "cd boot". Follow that command with "bootsect /nt60 X:" (with X being the drive letter). Let it return the prompt, and copy/paste all of the files from the ISO to the flash drive.
15) Take the flash drive out of the computer and place it into your Mini 10v. I am assuming that you are using Chameleon 2.0, so when you are starting up, interrupt the boot process and choose the sole Windows drive. Start up into that.
16) The Windows 7 installer will launch, and select "Custom install". This is where you might mess something up, as you will be reformatting a drive. Select the FAT32 partition, and reformat it as NTFS. BE SURE TO SELECT THE WINDOWS PARTITION, NOT THE PARTITION FOR OS X! If you do reformat your OS X partition, then all of your files in OS X will be deleted.
17) Install Windows 7 on the partition.
18) Once it finishes (after several reboots; that's normal), configure 7 to your liking. Aero and most of the functions of your netbook should run without any configuration.
19) You may have noticed that Windows 7 does not show Chameleon anymore. This is expected, because Windows 7 does not play nice with OS X. So you will have to do some work.
20) Download a bootloader to another flash drive (I used the aging Type11 loader, but Chameleon will work as well) and start up into that flash drive. Choose your OS X partition, and start up into your admin user account.
21) Go into Terminal (/Applications/Utilities) and authenticate yourself by typing in "sudo -s". If you haven't run sudo before, you will get a message. Ignore it, and type in your password. Also ignore the fact there are no characters; Terminal does this.
22) Type in "diskutil list", which will bring you into a program similar to the Windows program you used.
23) Note the numbers of your OS X drive, and then type in "fdisk -e /dev/rdiskX" (replace X with the drive number)
24) Ignore any error messages, and type in "p". Then, note your OS X partition number and type in "f 1" (assuming it's partition 1; replace your number here).
25) Type "write", "y", "exit" (each with it's own line)
26) Shut down to apply the changes.
27) You're not done yet, though. Restart from your flash drive and start into OS X again. Rerun the NBI installer, but only install the Chameleon RC3 bootloader.
Congrats! If you followed my guide correctly, it should start into either OS X or 7.