Spaghetti Western Steampunk? Actually, looking at the gent in Confederate uniform, the Italian Unification / Risorgimento uniforms can be very similar to Civil War / Reconstruction era uniforms, if not downright identical for some very specific regiments. I wonder if period US Civil War garb is somewhat facile to produce among Italian Steampunks. I'm not sure about the Indian Wars Period and thereafter. Sadly, I don't see much correspondence with American Steampunks; this historical topic (Risorgimento) contemporary to the 1860s is not taught very well (at all) in the United States. Same situation as with the Second French Intervention in Mexico, it's a subject completely overshadowed by the American Civil War in the education curriculum - by that I mean entirely ignored at secondary level schools.
A bit of trivia on the history of the red Garibaldi Shirt seen during the Wars of Italian Unification and its relationship to Latin American Independence and the United States Civil War:
The red shirts were started by Giuseppe Garibaldi. During his years of exile, Garibaldi was involved in a military action in Uruguay, where, in 1843, he originally used red shirts from a stock destined for slaughterhouse workers in Buenos Aires. Later, he spent time in private retirement in New York City. Both places have been claimed as the birthplace of the Garibaldian red shirt.[1]
The formation of his force of volunteers in Uruguay, his mastery of the techniques of guerilla warfare, his opposition to the Emperor of Brazil and Argentine territorial ambitions (perceived by liberals as also imperialist), and his victories in the battles of Cerro and Sant'Antonio in 1846 that assured the independence of Uruguay, made Garibaldi and his followers heroes in Italy and Europe. Garibaldi was later hailed as the "Gran Chico Fornido" on the basis of these exploits.
In Uruguay, calling on the Italians of Montevideo, Garibaldi formed the Italian Legion in 1843. In later years, it was claimed that in Uruguay the legion first sported the red shirts associated with Garibaldi's "Thousand", which were said to have been obtained from a factory in Montevideo which had intended to export them to the slaughter houses of Argentina. Red shirts sported by Argentinian butchers in the 1840s are not otherwise documented, however, and the famous camicie rosse did not appear during Garibaldi's efforts in Rome in 1849–50.
Giuseppe Barboglio a Red Shirt volunteer of the Thousand wearing the Marsala Medal
Later, after the failure of the campaign for Rome, Garibaldi spent a few years, circa 1850–53, with the Italian patriot and inventor, Antonio Meucci, in a modest gothic frame house (now designated a New York City Landmark), on Staten Island, New York City, before sailing for Italy in 1853. There is a Garibaldi-Meucci museum on Staten Island.
In New York, during the pre-Civil War era, rival companies of volunteer firemen were the great working-class heroes of the city. Their courage, their civic spirit, and the lively comradeship they demonstrated inspired fanatic followers throughout New York, the original "fire buffs".
A typical patriotic communal monument to the Garibaldini, at Monte Porzio
Volunteer fire companies varied in the completeness and details of their uniforms, but they all wore the red flannel shirt. When Garibaldi returned to Italy after his New York stay, the red shirts made their first appearance among his followers.
Garibaldi remained a local hero among European immigrants back in New York. The "Garibaldi Guard" (39th New York State Volunteers) fought in the American Civil War, 1861–65. As part of their uniform, they wore red woolen "Garibaldi Shirts" – at least, all enlisted men did. The New York Tribune sized them up:
The officers of the Guard are men who have held important commands in the Hungarian, Italian, and German revolutionary armies. Many of them were in the Sardinian and French armies in the Crimea and in Algeria.
Giuseppe Barboglio a Red Shirt volunteer of the Thousand wearing the Marsala Medal

PS
May I suggest changing the title from "Teampunk / Cowboy Crossovers" to "Steampunk / Cowboy Crossovers"?