The Acer Aspire 1420p is a nice candidate for the Windows 8 Developer Preview because it has a touch screen with two touch points. If you’re the lucky owner of one from the Microsoft PDC 2009, Windows 8 installs just fine. I used the flash drive from the BUILD conference as the boot drive, which installs the Windows Developer Preview with Apps and Tools (x64 version), which should suffice for most installations. If you want to install a 32-bit version, create a bootable flash drive using the instructions at the hyperlink below. Notice that the 32-bit version fits on a 4GB flash drive, unlike the 64-bit version.
The only trick to the 1420p is that it can boot from any of the two USB ports. The boot options for flash drives are listed FDD at the end of boot list when you enter the BIOS (pressing F2 during the startup sequence). I recommend to move both FDD options to the top of the list (pressing F6).
After that, you can follow the instructions on http://lifehacker.com/5840387/how-to-dual+boot-windows-7-and-windows-8-side-by-side.
I shrank the Windows 7 Ultimate partition and gave Windows 8 64 GB of space. Once the installation completes, the touch screen works fine but there are physical limitations to use the gestures that are possible on the Samsung tablet provided at the BUILD conference. Any of the gestures that are executed by swiping your finger from any of the edges of the screen into the screen (charms: swipe from the left; switch apps: swipe from the right; app bar: swipe from the bottom; bring up options for an app: swipe from the top) are very difficult due to the limited space between the edge of the touch screen and its frame (about 1/4 inch). You can resort to using keyboard shortcuts (http://www.windows8news.com/2011/09/16/windows-8-keyboard-shortcuts/) or use the stylus included with the 1420p. Even with the stylus, the swipe-from-the-top and swipe-from-the-left gestures are somewhat troublesome.
The gesture to switch between applications (swipe-from-the-left) can also be performed with the mouse: let the mouse pointer rest on the left side of the screen for about one second and a little window appears that lets you select the next application.