This mod is not for the faint of heart, but if you're really in love with that Palm Touchstone charger, you might be able to use it with your Sprint EVO.
The website Good and EVO came across a user who did the mod. It involves taking some contacts off the back of the Pre and soldering it onto the EVO's back cover. They say it took about a half hour, but could be done in as little as 5-10 minutes.
As you can see in the short video he has the mod working. Crazy? Maybe, but it's way cool!