The Marlin 1894 is the pistol caliber model. It's smaller than the 1895 action and has been made in modern times in .44 mag, .357 mag (the two most common, .45 Colt, .41 mag, .32-30 and .25-20. The last four calibers were limited production numbers. There were only about a thousand .45 Colt 1894s built. Probably about the same for the others, give or take a few hundred. These are not the recent "Cowboy" 1894's in .45, .41, etc. They were standard commercial models (i.e. no cowboy features) made in the 1980's and are valued by Marlin collectors. I bought one of the .45LC ones back in the '80's and they are a very nice gun. Much handier and quicker than the cowboy model.
The .44 mag 1894s are pretty easy to find. They are the most popular by far, though you can run across a .357 every once in a while.
The 1894 in .44 mag would be a great little gun. Plenty of power at short range, and the action size is very efficient for a pistol cartridge. There's no wasted extra action length, or weight, with the Marlins as there is with other leverguns.
I don't know what they are making right now, but the short carbine is the way to go IMO for these smaller calibers.
Ross