After perusing Jay Miller’s “Aerograph 4 Convair B-58” he does list one MB-1C free fall bomb pod modified by Convair for special testing of the encapsulated ejection seats of both the B-58 and the XB-70. It was nicknamed the “Guppy Pod” and used after mid June 1961 at Edwards AFB in successful testing of the seats.
There was nothing about using the pod for VIP flights. My feeling is that the pod would have been cramped with all the associated testing equipment.
There was a study of developing a “People Pod” in 1960 with room for 5 and testing equipment to be used for study of the “subjective reactions“ of passengers at supers cruise. It doesn’t appear to have advanced beyond a paper study.
There were no pictures of a B-58 painted in the SEA camouflage in the book, just a small illustration showing the overall scheme and colors.