If you could tolerate a 22" barrel, I'd look for a Browning 1886 SRC. These were made for Browning by Miroku in the late 1980's. You can find them on Gunbroker all the time in top condition for around $900. They are beautiful, well made rifles which can handle any modern 45-70 factory load. I have one and it is one of my favorite rifles. I've handled the Marlin guide guns (which are nice) and I find the '86 to be a superior rifle.
Miroku still makes an 86 under the Winchester brand, but they have that silly tang safety and a rebounding hammer. Opinons vary on the quality of these newer reproductions.
If you can't trust a John Browning design, who can you trust?
Pancho