Rena Kryze
The Quartermaster

Image Source: http://www.deviantart.com/art/Mass-Effect-3-Omni-Tool-Reference-333008257
Intent: A tool for engineers, especially of the Mandalorian variety.
Development Thread: If necessary
Manufacturer: MandalTech
Model: MT-TX Omni-Tool
Affiliation: Mandalorians & MandalTech-approved buyers
Modularity: Tool and interface colour
Production: Limited
Material: Durasteel (or mounted beskar'gam), hologram/laser components
Description: When multiple tool modularity was required, the ubiquitous multi-tool was the original standard in portable repair. However, when a Mandalorian needs to fix something and fix it but good, then they need a solution even more powerful. Enter the omni-tool. The omni-tool is not actually a physical tool, but a hologram-based tool. It employs rare but powerful solid-state hologram technology that is governed by a control panel (also, funnily enough, a solid-state hologram interface). This interface determines power, length, size, shape and function of the tool, which uses sliders and selector menus with a pop-up menu over the control panel controlled by the fingers. With this interface and highly specialised technology, it is not actually multiple tools, but a single tool that can change size, shape and function with a few presses of a button - in this, it renders most physical limitations of tools moot. These tools can rotate, move back in a near-pneumatic fashion, or otherwise function as need be to perform functions.
The omni-tool, thanks to this, has a staggering selection of available tools programmed into it - and these tools can change size to fit as need be. With the modulator function of the omni-tool, it can use the functions of many tools, including a hydrospanner, laser spade, laser drill, energy tether, servodriver, turbohammer, hydrogrip, micropoint, laser calipers and laser shears - and, if the tool is reasonably small in scale, chances are an omni-tool can do it. Given that holograms are, by nature, laser-based devices, it can amplify the laser's power to also function as a cutting laser or a laser welder.
The drawback to this item is that it takes up a reasonable amount of space and power. Two power cells similar to that used by a lightsaber are required for this device - meaning that this is a bulky device to mount either onto or into to a beskar'gam's wrist and, depending on the quality of the armour involved, may render an arm unable to use additional equipment. For those unwilling to directly mount it, the omni-tool is available as a device that can be strapped to the wrist, meaning that it can be used by engineers on the go. The omni-tool is also a power hog; before outright replacing both power cells, it can go for ten continuous hours (and, as a side-note, using the 'amplified' tools cuts that continuous operation time to one-third). Obviously, these are not massive industrial-grade tools, either. One could use it to build a weapon, a beskar'gam, or perform standard starship repair - don't expect to be assembling massive hull plating or cutting through a heavy blast door with this. So too are these expensive to produce, making their production run limited - generally made to order.
One nifty feature is that, being a holographic device, it does come with a holocom installed too as a bonus for customers.