FrankS, yes a Ruger No1 can be converted even to a .500NE 3", plenty have been done here in Oz! They are a sight on the rifle range. With what appears to be a short fat barrel; in reality most are longer than standard, just the action length shortens the whole unit overall making them a very handy package.
Well you certainly have some ideas thrown at you & the ideas are all sound!
Your decision is the final one though as to what you really want; but then again its like a spanner, you have all different sizes for different bolts - same principle for rifles I reckon......well until the wife finds out!
Tough decision mate, after all it is a 'Big fifty" you're after
93x64mm