The look of the styled fender makes me think it is a Root. My uncle bought one from the local IH dealer and I mowed lots of lawn with one similar to that one, except the one I used had 2 front wheels. I know they had a one wheel model too. I think Root Mfg. was somewhere in Nebraska or mid plains state. I just have never found one around here (55 yrs later), so my thinking is you should buy it!
Not directly related, but this thread on the Jalopy Journal might give you some ideas what can be done with an uncommon mower.
Thread is 13 pages long, and I suggest you peruse it all for posts from the original poster, just to follow along with his build.