startup - Method to create a live USB disk (with persistence) which actually works?

I've tried so many combinations - all I want is a fast Ubuntu Live USB disk with persistence that works. What I've tried so far:

• Using unetbootin on my Mac, choosing some "Space used to preserve files across reboots (Ubuntu only)".
  
  
  
  • Result: Doesn't boot at all.
  
  


• Using unetbootin on my Mac, choosing no such space.
  
  
  
  • Result: Boots fine and very fast (doesn't even show the annoying dialog "Try ubuntu/install ubuntu" at startup!), but has no persistence. (So I have to choose my keyboard layout, install programs I need, etc. every time)
  
  



• Using Startup Disk Creator from my Ubuntu 11.04 installation.
  
  
  
  • Result: I cannot choose "reserved extra space" at all. It's greyed out. I know I know, there was bug 557775, and many people say that the workaround from comment #4 works for them. But it doesn't work with Ubuntu 11.04 anymore (see also comment #14).
  
  



• Using Startup Disk Creator from my Kubuntu 10.10 installation, gnome version (usb-creator-gtk).

  
  
  
  
  
  • Result: I can select the "reserved extra space" option, but installation doesn't work (fails when installing the bootloader).
  
  



• Using Startup Disk Creator from my Kubuntu 10.10 installation, kde version (usb-creator-kde).

  
  
  
  
  
  
  • Result: Actually works: Reserved space can be selected, installation works. But after booting, I get the screen "Try ubuntu/install ubuntu". Clicking on "Try ubuntu" takes me to the desktop - but only after waiting 5 minutes (every time!). It also doesn't seem to keep my keyboard settings.
  
  

I know, that instead of creating a startup disk, I could install a full ubuntu system on the USB stick. But as far as I know, this isn't very good, because /tmp and similar directories will then also be on the USB disk, which is a) slow, and b) not very good for the USB disk due to frequent overwriting.

I'm frustrated. So has anybody managed to create a working Ubuntu 11.04 Live USB disk with persistence?

I've used a 1GB flash drive and because of the sheer volume of the ISO image compared to the space on the drive creating some persistent space is not only next to impossible it's also just not feasible because you'd have a VERY small amount of space for stuff to save off to. Grab a 4 to 8 GB flash drive, put on the ISO using the Ubuntu built in USB startup disk maker and it should work. At least it did for me.

One other thing you can also try (I've done it so it should work.) is take an external HD that you can plug into the system via USB (Like a Western Digital backup drive for example.) and then what you do is take out the HD from your pc, plug in the external one into the usb ports, and then you (should be able to) install to that external drive from the ubuntu install menu. Then when you're all said and done you've got an external hard drive that is persistent because well, it's a whole OS!

I would also recommend that you take a look at the following link/question. It goes into a bit more detail on how to do what you're asking... Points down to the link

Install Ubuntu on USB Flash Drive or USB powered external HDD?