Looks like there is a another alternative to Magicbutton and vBar from HTC. The tool posted on XDA Developers for the HTC Hermes seems to work well on the X51v and does a good job of being yet another "close really means close" utility. It is larger than vBar, smaller than Magicbutton and lacks almost all of the advanced features of either, but it makes up for it in simplicity and the fact that it doesn't seem to have the problem with the Dell WLAN tool that Magicbutton suffers from.
It has a simple idea and only a couple of options, you can either have tap-and-hold to quit an app, this is the default and leaves the standard operation for a quick tap as minimise, or just tap to quit. The settings can be found in the Control Panel at the bottom of the System tab, look for "X-Button"
Get the tool from
http://forum.xda-developers.com/showthread.php?t=283658
Direct link:
ftp://xda:xda@ftp.xda-developers.com...20X-Button.CAB
I did find an updated version on their ftp site under the Wizard uploads folder, but it did not seem to work properly on the X51v.