Lefty,
Understand, regarding the cost of machining and welding. I think I'm going to take to calling the broken part the "collar" for lack of a better term (until someone corrects me about five minutes after writing this). The problem that I think exists is that the thickness of the collar may be about all there is between the cylinder wall and open air at the base of the fins. Bore out that much and you could end up with a stack of fins laying on top of the base flange. Also, I would think the cost of boring out that much material would be equal to or more than spinning a tube to the right ID/OD and brazing or welding in place. Anyway, waiting to see if you can find one that needs less work may be the right choice. Though, you would probabaly be giving up starting out at standard bore with, maybe, three rebores possible. (I don't know if you could actually take 0.030" from the 0.094" wall for the 60-over rebore.) If you put yours up on Ebay, someone with his own shop (could even turn out to be one of our members) will buy it, fix it and use it.