Hi Troll,
Is that your model? NICE
Split race bearings.....in a qaulity level high enough for a lathe, are going to be expensive....REAL expensive.
Additionally, a radial roller bearing like that with a split race sounds like it's asking for trouble, The contact stress at the joint when a roller goes over it will be very high. If that race is not supported correctly and evenly, you'll see every roller as it leaves a mark in the part you are cutting.
Now the Angular contact roller bearing is another story. Many lathes have used just that. Class 00 roller bearings aren't cheap either.
I have to wonder how much time and effort would be required to make all this happen though. Still might be cheaper to go with the factory bronze?
Dave