How about a pair of 1911's? Colt, Les Baer, Wilson or some other established manufacture.
Re: firearms as investments. I wish that I had purchased some of those Steyr AUGs that were at the shows for less than $1000.00 20ish years ago. I know a few years ago they were over 5k. Or my first duty weapon. A 686 in the midnight black finish. I paid $175.00 NIB for it, last time I saw one it was over $750.00 and beat up bad. I paid $400.00 for a High Standard 10B shotgun and sold it for $1200.00 after a couple of years.
I have made too much money off buying firearms and flipping them for a profit after a year or two to believe they are not a sound investment.
Look at what happened with 696s and 940s. A few years ago these could be had for a song, now look at the prices they command even in well used form.
In my area I am seeing more and more of the Nightguard revolvers for $600-700.00 (mostly the 610) when a year ago they were 1k when you could find them. Before long I will find one closer to $500.00 and jump on it, sit on it and flip it for a profit.
Quality firearms go in cycles just like any other investment. By quality, by low and sell when you think it has peaked. It doesn't have to be exotic to gain in value. Plain 686s have been on the rise for a long time. Colt 1991A1s have about doubled in 10 years. Or even look at SKSs. A Russian SKS was around $85.00 15 years ago. Those same ones are pushing $500.00+ now.