Depending on where you live in the nation, the idea of creating a "shotgun" position is not only practical, but is already being done. Some states have special officer capacities which, for all intents and purposes are volunteer positions with reduced training and authority as compared to a level one or ywo reserve officer in states such as Florida and California. In these states, reserve officers, when on duty, are fully sworn officers with the same level of authority as full time police officers. In the case of level one officers, they can patrol on their own, handling the same calls as their full-time counterparts. In the case of "special police," as it applies, the positions would be fulfilled by qualified volunteers whose training is geared towards the needs of their function. In this example, the individual, upon a successful background check, physical agility and other appropriate tests would undergo the same defensive tactics, firearms, cuffing, take downs, restraint holds, baton training, etc., as a full time officer, minus the areas they will not have the authority to perform. In the case of a domestic violence call, the special officer does not need to know every subsection of the law regarding DV cases; however they do need to know you don't stand in front of the door when you knock, you always keep the two (or more) parties separated, you never let them near the kitchen or sharp objects, you never turn your back on any suspect, and of course, always protect your partner's back as that is your primary mission. Likewise, when conducting a traffic stop in the "shotgun" position, you don't need to know the exact vehicle code your full-time sworn officer partner is stopping the driver for, but you do need to know how to approach the vehicle, make sure the trunk is closed, always watch the hands of the occupants, look for a cover position in case you do end up in a gun battle, etc.
I object, your honor
While many questions, such as "What kind of uniform would they wear?" and "What do we call them?" may arise from this thinking, the biggest obstacle may come from the very people they would be there to protect--your fellow full time officers. If no one else speaks out, you will most likely get feedback from your agency's union rep, which of course is their job to do. The bottom line is this is not a ploy to bring in lesser-paid police officers, thus creating a two-tiered system. It's simply a method to help protect your agency's biggest investment and the lives of these very brave officers, with a program that could be up and running within a year's time frame. For agencies who are short on manpower and offering generous incentives for laterals, or are reducing their standards to attract more people, this is one consideration which will provide you the additional cover you need on the street until you can fill the ranks with qualified full-time sworn officers, without giving away the store or lowering your standards to do so. An additional benefit to consider is this may provide you with a "farm team" to recruit from, as you'll know first hand who within the "special police" ranks you'd want as full time officers.
While this method clearly is not for every agency and may not be for yours, for agencies whose staffing shortages are causing an officer safety issue with no resolution in sight, you may want to consider looking back to western history for a simple, yet effective measure to help protect your most precious assets with a shotgun rider.