Is this an Android version specific? (ie Gingerbread)
No, this has nothing to do with the Android version, I have several close to me and none have such option. It's probably a carrier-specific setting on the stock app.
bahamat answer easily justifies the reason as to why carriers would prefer such low limitations and how this benefits users.
Is this a configuration one makes when setting up a device with the Android OS regardless of the version? Meaning every device is different?
It may vary depending on the device and carrier, but what usual happens with settings like this is that they are silently applied, but as you've found out, the user can update the value to a more desired one.
How many devices are set with a max file size this low, what's the standard setting out of the box?
There's no standard about the size for an email that goes this low. What actually exists is a general conception regarding the emails maximum size that accounts for the sum of the message's body and the encoded attachment.
Since a message will often pass through several mail transfer agents to reach the recipient, and since most of them have to cache messages for a certain period of time, this brings storage issues that need to be addressed. Since the early days, 10Mb was considered to be more than acceptable for an email.
You can read all about this at Wikipedia.