To get the behavior you want you need to do a few things in addition to stopping the pop-up delay:
Install CCSM if not installed already. apt-get install compizconfig-settings-manager
from the terminal or search for "Advanced Desktop Effects Settings (CCSM)" in the Ubuntu Software Center.
Select the System Settings option in the power button menu (top right corner) and launch CCSM from there.
For Ubuntu 13.04 (Ringtail)
This may also work with > 12.10; unfortunately Unity changes significantly between versions.
Select the 'Ubuntu Unity Plugin' in 'Desktop'.
Under the 'Switcher' tab un-tick 'Show live previews of windows in the switcher'.
I'm not sure the popup delay exists in 13.04; I don't seem to notice any on my machine at least.
This section also allows you to swap the bindings of the switcher for all viewports and the viewport switcher.
For Ubuntu < 12.04
Select the Static Application Switcher in 'Window Management'.
Under the 'appearance' tab check 'icon' and 'show icon only'
And as @fossfreedom said, you can get rid of the .2 second delay "feature" under the 'behavior' tab by reducing 'popup window delay' to 0.
If you don't want them in rows you can switch to the 'application switcher' and change the settings similarly. Just make sure you do this by de-selecting the 'static application switcher' first, or else you'll get binding conflicts.
Best Answer
As far as I know...the size of the default "Switcher View (Alt+Tab)" is hardcoded in the Unity source.
You can try to edit the source code to change the size according to your needs.
NOTE: I recommend you to do this in a Virtual Machine or in a Test Machine to see if you get the desired results.
In this example I'm running Ubuntu 13.04 with unity 7.0.0 and I will change the "Switcher View" (icons, tiles, etc.) to the half-size.
1) Make sure you have enable the Source code repository.
Open a Terminal window Ctrl+Alt+T and type:
sudo apt-get update
2) In the Terminal type the following to install the necessary packages.
sudo apt-get install build-essential python-windowmocker quilt
3) Install build dependencies.
sudo apt-get build-dep unity
4) Create a folder to download the source code.
mkdir ~/Downloads/src
cd ~/Downloads/src
5) Download the source code & Export variables.
apt-get source unity
export QUILT_PATCHES=debian/patches
export EDITOR=gedit
6) Create the patch and Edit the source code.
cd unity-7.0.0daily13.06.19~13.04/
quilt new 99-custon-switcher-size.patch
quilt edit launcher/SwitcherView.cpp
Edit the lines... 46 to 50.
I changed them from:
To:
7) Build the deb packages.
quilt refresh
fakeroot dpkg-buildpackage
8) Install the deb packages.
cd ..
sudo dpkg -i *deb
9) Finally you can Restart your machine to see the changes.
Before:
After:
Hope this helps.