You might consider looking at the thread below. Although it is in the "Apex" portion, it is not about those products - is strictly about the hardware. It is quite lengthy, so you may just want to pay attention to the last few pages (?).
Also, FWIW, I generally have a personal preference for the ThinkPad line over the Latitude line and that is also what most of our "Enterprise" customers tell us, as well, but my & their needs may not reflect yours. My observation is that most fee appraisers put initial purchase price at the top of their priorities, but many times, factors such as your environment (primarily sunny, wet, hot/cold, coastal, etc.) will ultimately point to certain devices over others as being the best value. Also, making a decision as to whether the device is more of a "desktop replacement" or mainly a field/mobile "companion device" is helpful in bracketing a price range as may the availability of cases, 4G/LTE, etc.
Hope this helps! Feel free to post any questions in the forum linked above as you may get some useful feedback there from other experienced fee appraisers who have wrestled with some of the same items you may be facing.