the .45 acp luger is a holy grail of collectors. there were very few made, so finding one would make your day. i'm surprised no one has made a replica yet. it'd be really cool to own one. even the 9mm ones are outrageously expensive now. i almost bought a cased 9mm naval luger in 1970 for a couple of hundred dollars in san diego (it had a couple of mismatched part no.s) while i was there on a navy training course (in turbine engine maintenance). sadly i found it 4 days before i was to leave for alaska, and it would have taken 5 days to go thru the paperwork bullpoo.
In 1906 and 1907, the US Army held trials for a large-caliber semi-automatic. DWM provided two sample Luger pistols chambered in .45 ACP for testing, with serial numbers 1 and 2. The fate of serial number 1 is unknown, as it was not returned. The serial number 2 Luger .45 passed the tests, and survived to be traded among collectors. Its rarity gives its value of around $1 million US dollars at the time the "Million Dollar Guns" episode of History Channel's "Tales of the Gun" was filmed, recheck by Guns & Ammo as of 1994.
At least two pistols were manufactured later for possible commercial or military sales, and one is exhibited at the Norton Gallery, in Shreveport, Louisiana. The other was sold in 2010 and remains in a private collection. After initial trials, DWM, Savage, and Colt were asked to provide further samples for evaluation. DWM withdrew for reasons that are still debated, though the Army did place an order for 200 more samples. A single .45 Luger carbine is also known to exist.