Easy way to update computers?

Hello,

Like a lot of you, I end up supporting a whole bunch of computers for
friends/neighbors/family/etc. Is there any way to use some tool to
automate the installation of updates when I'm visiting to fix computer
problems?

Yes, I turn on automatic updates whenever possible, but a lot of users
turn of their computers or still have dial-up and don't want to wait...
whatever the reasons, here's what I'm envisioning.....

At home, I run some tool which goes out to MS and sees all there is for
whichever operating system(s) I want. Then it downloads them. All of
them. Or, at least the ones it hasn't already in it's directory. then,
I burn it to cd or put it on a usb drive and go to uncle joe's. I put
in the cd or whatever, run the tool. It recognizes what needs to be
updated and asks for confirmation. I get a beverage and come back in a
few minutes and take my cd and life is good. No repeatedly going to
windows update and waiting for everythig to download, it's all right
there.

And yes, I know I can select the patches I want from the windows update
catalog, but that's tedious, I could miss some, and there still needs
to be an easy way to identify the needed patches on the target computer
once I get them all there.

So, does such a beast exist?

TIA,
--Kevin