Another method you might consider is epoxy (JB Weld) the base to receiver. This serves a dual purpose of bedding the base and securing it. Making sure the base is level is critical, of course, before curing. I know some Eurpoean snipers do this for Picatinny rails on the German G3 action.
That was a crappy job , I'd be suspect of how hot he got the reciever or how cold he made those welds.
The only real benifit would be a one piece base as it may stiffen the action , if TIG welded properly you can do it safely , not anymore dangerous than weldingthe lug to the bottom of and Encore barrel and I've done a couple of those.
Good aluminum bases with good steel screws is as strong as you need , you break that off and your scope is gonna need a bit more than alittle buff to make it right.
Some of the reasons are,The heat generated could change the heattreat
of the action,Welding stresses could warp/distort the action,Matching the
steels and the welding rods/wire would be difficult if not impossible.
It would be best to just buy an action with the scope base that is part of
the action and alligned with the bolt center line.
Stiller,RPA,Surgeon and Stolle make a action with integral scope bases.
Even though these are a little more expensive than a factory action
they could end up cheeper after you ruined a factory action and had
to buy another action.