The Gloucester one (google Chasing the Morning Sun) was an RV6 ... sounds like an amazing trip, one for the "10 things before I die list" ...
Read on a SA based forum (not Gunn's) of a fellow that may be contemplating going for this record in his RV6. Not sure if the SA homebuilt regs also specify day/vfr though. Out of interest, do the Americans allow IFR certification of their experimentals? Might have a hard time convincing the UK CAA to allow that sort of thing ... but maybe with careful planning one could get through the United States of Europe VFR, then do the African legs IFR?