[T-Mobile LG G2x] EEngineer:
For the most part, ICS/JB is a user interface change. Pleasant looking menus with a cool blue color. There are quite a few options out there to give your G2X the look/feel of ICS/JB but I had my eye on efficiency.

The Ice10 Theme and Holo apps are easy on the battery and use little additional CPU. Of course, if you increase cache sizes and use fancy transitions YMMV. But I'm quite happy with my ICS/JB themed phone.

1. Start with the latest CM7 Nightly. I don't know if this works with other ROMs, but it should. GB7.2 is recommended.

2. DO A NANDROID BACKUP

3. Install the ICE10 Theme: http://xdaforums.com/showthread.php?t=2003484

. . This gives you some of the ICS/JB look/feel.

. . Put the Ice10.apk on your SD Card, click to install. Then start the Theme Chooser app, select Ice10 and click Apply.

. . If you get a theme error that you are missing assets for your screen size, just click Apply Anyway. Reboot phone.

4. Install Holo Launcher: https://play.google.com/store/apps/details?id=com.mobint.hololauncher

. .Holo Launcher on XDA

. .Holo Launcher is a brilliant app that gives you the ICS app drawer, screens, and menus. The screenshots don't

. .do it justice, it looks even better than that!

5. Install Holo Locker: https://play.google.com/store/apps/details?id=com.mobint.locker

. .Holo Locker on XDA

. .This gives you the ICS lock screen!

For the Ice10 Theme, the G2X resolution is already 240DPI so no changes are needed.

I paid for Holo Launcher Plus because the full ICS/JB experience is well worth the $1.99. It includes additional transitions and improvements. Holo Launcher is insanely customizable! The dock is scrollable and can have up to 10 icons. The Desktop and Drawer each have settings for the "scrolling cache", which is none, Low quality, Normal quality, and High quality. All this really means is the higher the quality, the more RAM it uses to make the transitions faster and smoother You can also change the desktop and app drawer grid size so you can fit a hell of a lot more apps on your screen.

For both Holo apps, I recommend going into the Settings and disabling Auto check for Updates and Auto Report. I don't like my apps checking for updates in the background, uses battery and CPU.

The Ice10 theme XDA thread contains wonderful info on final mods you can make to truly have the complete and total ICS/JB look/feel. Keep in mind that isn't a G2X thread so some of the mods, like the final Menu mods, are phone and ROM specific, so someone would have to make those additional mods specific for the G2X and specific ROM.

The below screenshots are for my CM7 Nightly ROM. Notice how Holo Launcher gives you a dramatic difference in the Settings. The Menu button is also different and the menu options are completely customizable.

Sorry for the lo-res Starship Enterprise wallpaper but it was a camera photo taken of the TV screen some days ago. Zooming in lost lots of resolution.

This is really a fantastic mod. I have all the user interface benefits of ICS/JB while having a totally operational phone with HW acceleration. I really don't need or don't care about using any other ROM at this point, although I'm waiting for Mazout's next kernel.

Thanks to EricTheLuminant for pointing me in this direction.

Remember to THANK ME if you appreciate this!