We already demonstrated that you can change the accent color or theme on HTC (but complicated) and Samsung phones, but now Dave Amenta has also added LG and HTC support to his simple app Accent Changer..
It's the same deal as before, you need to have a developer unlocked phone to sideload the XAP file, but once you do so you can simply drag your finger to manipulate the color gradient. Heck, you can even restore the original value with a touch of a button.
And now that LG and HTC devices can join in, the circle is complete (Oh right, no Dell, sorry). Read more and grab the XAP here.