My fat fingers and a small allen wrenches don't work well together. I've never come across a nice small T-handle set that isn't too big/long to get into the Replicator spaces. This Thing gives small allen wrenches a bit of a handle to make them easier to ... handle.
There is also an alternate screwdriver-like round handle.
Included are .stl files for five small wrench sizes, and it shouldn't be difficult to change the .scad files for any size you want.
The .zip files include .stl files for both T and Round handles for wrench sizes: 1.25mm, 1.5mm, 2.0mm, 2.5mm, and 3/32in (2.4mm).
The .zips also include the .scad for T and Round. They are somewhat parametric; remove/add comment marks to select handle size and wrench size.
I haven't printed the round handles, but there's nothing special there; should work just like the T's.
Print the halves and drop the wrench into one half. It will probably take a little bit of cleanup work with an x-acto knife to get the odd threads and bits out of the slots to get the wrench to fit well. Add a couple of drops of CA adhesive to the wrench/slot and press the halves together. Peel your fingers/skin off the handle 'cause you used too much CA.