You might want to consider looking into the Traynor SB500, made in Canada, and by all reports sounds very similar to the GK MB line. I have not played one, but over the years I have always had great luck with Traynor/Yorkville products in terms of performance and bulletproof reliability.
That said, the 700RB GK heads are iconic for many reasons and one of them is reliability IME. I would look for a reasonable deal on one that is in good shape... and be sure to specify in your will who gets the honor of inheriting it.