Jeeze........
I spent ALL of last night looking at all this stuff. My conclusion, there are too many different tracks variation and tape widths to simple lable a machine MX5050.
No really...
There are some OLD machines out there in 1" 8 track format. Some look nice but I think would be a pain in the ass to fix when they break. Not in a technical spect, but part wise.
Scully look cool....OLD....but cool. Ampex.........I am not even getting my self into something like that. They probably stopped making parts for it long before I was even born.

Studer.....couldn't find one on ebay but I could never afford something with that name anyways.
Then there was the MCI JH series
Now I am aware that their 2" 24 track machines are consider to have the worst frequency response of all 2" 24 tracks out there, but they have a nice looking 1" 8 track and.....even a 2" 16 track. I think the cost of tape is going to keep me from 2" all together.......but a guys gotta dream right.
I am going to look to see if there are any 4 track half inch machines. But it seems like a lot of this stuff ceased production by the mid 70's.