Hello Paul,
As several of the other fellows mentioned, your best bet at finding an original Winchester high-wall takedown at a "reasonable" price, is a Second variation high-wall Winder Musket. I also agree that the strength of the frame and action is not an issue.
Just to give you an idea of what you are up against (in an effort to find an original), I have surveyed 5,253 original Winchester Model 1885s. Of that number, exactly 116 were high-wall takedowns. Broken down into precise numbers by variation, they fall out as follows;
39 - 2nd variation High-wall Winder Muskets
27 - Third Model Schuetzen Rifles
26 - High-wall Shotguns
21 - Plain Sporting Rifles
2 - Special Sporting Rifles
1 - Special Single Shot Rifle
I own one of the Plain Sporting Rifles (the pictures below)... and no, it is not for sale
(You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) (You need to Login or Register to view media files and links) It is a real odd-ball rifle in that it is a high-wall, chambered for 22 Short, with a 24" No. 3 octagon barrel, and it is an early enough serial number that I was able to get a factory letter for it.
Bert