Regat.exe is a command line utility that opens "regedit" at a specific location. You may specify the location on the command line or, if you don't, it will check the clipboard for one. Some abbreviations for the leading part of the key are supported as well.
Update: Apparently the Sysinternals guy put out RegJump at or around the same time I made mine. Creepy.
Syntax: regat [KEYNAME]
(KEYNAME may be omitted if there is a key in the clipboard)
You may abbreviate using HKCR, HKCU, HKLM, HKU, HKCC
regat.exe v0.2 Apr 23 2015
See http://www.elifulkerson.com for updates.