Give it slightly more Rheinland features, slap on a green engine effect and do this:
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As the Rheinland government realized they were on the losing end of a war of attrition, it began searching for ways to turn the tide. In a decision of desperation, the government contracted Kishiro Industries in Kusari, and leased production facilities from Daumann and Kruger to produce the <name>, Sirius's first private civilian gunship.
Rheinland's plan was to put the heavily subsidized <name> in the hands of as many willing and able private Rheinlanders as possible, with orders to defend their home space against any Liberty incursion.
Though this tactic proved successful in making Rheinland a truly fearsome place for Liberty patrols, an unforseen (or disregarded) consequence of flooding Rheinland with the <name> was its inevitable export. The <name>, can be found for sale throughout Sirius in various less-than-reputable shipyards.
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In this case, the gunship should be cheap, light, and ever so slightly underpowered vs. other gunboats. A mass-produced, inexpensive but flawed and perilous alternative for Rheinland homeland defense, and whatever else you can RP it to be.
I like the idea of a civilian GB, but there's no way it should ever be able to take down factions' GBs in a fair fight.