Problem in safe mode deleting users...

Question

I am prepping a few Macs to sell on eBay and wanted to remove the user files and get them to do the startup song and dance when the new user turns it on. I used the following commands in Safe Mode:
mount -uw /
rm -rf /Users/*
cd /var/db
rm .AppleSetupDone
rm .com.apple.iokit.graphics
rm -rf dhcpclient
rm -rf samba
shutdown -h now
All this works fine, except it does not delete any users. So, I tried a few other commands, I used this one:
dscl . delete /users/username
typing the exact user name, and I get this response:
dscl[6] *** Uncaught DS Exception: <(null)> (eServerSendError)
I tried deleting all of them with:
dscl . delete /users/*
and I get the same response:
dscl[6] *** Uncaught DS Exception: <(null)> (eServerSendError)
I tried using:
sudo dscl . -delete /users
and get this again:
dscl[6] *** Uncaught DS Exception: <(null)> (eServerSendError)
I tried using:
niutil -read . /users/
When I do that and hit 'return' it drops a line and does..... nothing. It just sits there and won't respond to any commands, the prompt isn't there. I wait, and wait, and wait and it just sits there.
So, I have two questions:
1. How do I delete ALL users in Safe Mode (I don't want to start the computer and create a new user after I've made the computer redo the AppleSetup dance).
2. Why in the HECK does the cursor just sit there, on a blank line, and do nothing after I issue the niutil command?
I suppose, if it isn't possible to do this in Safe Mode and it must be done in Terminal, then I could do this and then boot into Safe Mode and issue the other commands, if someone knows how to do this, but I'd prefer to do it all at once in Safe Mode (if possible).
TIA
PS In case someone asks why I don't just wipe the drive and reinstall OS X and leave it, it is because on these I wanted to update everything using Software Update so that when it ships it's fully updated. I wanted to update it completely and then restore it to "factory" state so that when the new user turns it on it does the new user setup and has no other user accounts on it.

Answer 1

No offense, but perhaps you ddin't read my whole post. Both of the links you provided (which I've read before) do not allow one to UPDATE the software and then return it to a state that has the AppleSetup launching on boot. If I wanted to load OS X 10.4 without updating it to 10.4.11 then those solutions would work fine, but that isn't what I want to do. I want to update everything - Tiger and all the software - as far as it will go and THEN return the machine to factory state. I could go into why I want to do this, but I won't bore anyone. The point is, I do.
Can someone that understand Unix commands on the Mac help me? Thanks.