Threw together something fun for you: a one-click (don't sue me, Bezos) app for enabling or disabling multitasking (no-dehydrate) on Mango. Fast app switching + full multitasking = awesome! Disabling multitasking when you need to save battery = convenient!
Credit to Jaxbot for working out the no-dehydration registry change. That's all this app is, just a convenient way to toggle that registry value.
I'm going to try to add support for more devices (Samsung Focus S and HTC phones that have lost the ability to use COMRegRW.dll).
UPDATE 1.1.1: Case sentitivity recognizing SAMSUNG now fixed, Samsung and LG confirmed!
UPDATE 1.1: Better Samsung support, possible LG support.
Secondary tile with deep linking! Shows current multitask state and toggles it when tapped.
Supports HTC, LG, Samsung phones.
HTC phones need to not have the latest HTC updates, as those break the Registry driver I used.
The latest DFT ROM works, and others that support TouchXplorer probably do too.
I'm working on a way to make it work with official ROMs as well - you can help out here: http://forum.xda-developers.com/show....php?t=1335862
Works on Mango! Uses no homebrew DLLs.
No Dell/Asus/Toshiba/Nokia/etc. support yet (find me a registry function and I'll add them, though).
Doesn't work pre-Mango; it's a 7.1 app (could be downgraded pretty easily).
Unpack ZIP file and find the XAP in MultiTaskToggle\Bin\Debug.
Install app on an interop-unlocked Mango phone.
Run app and ensure it loads the current value.
[Optional] Select the value you want; it will set immediately.
[Optional] Tap "Live Tile" button to create a tap-to-toggle secondary live tile.
This app is a simple wrapper for the OEM registry edit DLLs to make use of Jaxbot's hack. I wrote it largely just for familiarity with mango homebrew. The source is a bit of a mess right now - I took an existing homebrew library and beat it savagely until it worked on Mango, but didn't really put the pieces away neatly afterward - but it's simple enough I expect somebody else can use it for good things. Personally, I plan to make an app that allows easy general-purpose registry edits on Mango, though I still don't see any way to do registry browsing.
Thanks to XDA member MarysFetus for taking the time to do a visual overhaul of the app, with nice icons and such. It's much more artistic than my solid-color tiles with simple text! Grab the xap directly below. You can also visit the site: http://www.suicideclown.com
Thanks to XDA member singularity0821 for doing more visuals for the app, with a new (and flipping) live tile. I've included that XAP below as well.