Is there a specific reason why you are asking specifically for a '68 to '71 cabinet, and then say it doesn't have to be a collector's piece? That's virtually a contradiction to itself. All '68 to '71 basketweave cabinets are somewhat collectible if they're in any reasonable condition.
Do you just want a pinstripe spec 1960 Marshall cabinet or an exact clone of one?
There are people and companies that can make that, and you'll pay a lot less than buying any original in decent shape.