In the various download repositories, there are 10.04.1 ISO images of Ubuntu desktop, alternate and server editions, but I can only find the original ubuntu-10.04-netbook-i386.iso, not an updated ubuntu-10.04.1-netbook-i386.iso. Is the latter ISO available somewhere? If no, why doesn't the Ubuntu maintainers create one for this version.
Unfortunately, there is no netbook iso for 10.04.1. For some reason, unlike the desktop and server editions, Ubuntu Netbook 10.04 is not considered a Long Term Support (LTS) release. Though, all hope is not lost. If you install from the original ubuntu-10.04-netbook-i386.iso and apply all the updates, you will effectively have Ubuntu Netbook 10.04.1. If you look at 10.04.1's changelog, it includes many netbook fixes even though it is not a LTS.
I found a mirror that has a copy of it here:
My guess would be there is no 10.04.1 since an upgrade from CD or via Internet is available for the 10.10
Ubuntu Netbook 10.04 is not an LTS version (LTS is only "classic" Ubuntu and Ubuntu server) -- so there are no maintaince updates (10.04.x) for netbook version.
(The same as with Kubuntu 8.04.)
The official site will give you the newest, 10.10, or you can go here for 10.04.1 - http://releases.ubuntu.com/lucid/