On a more serious note, it would seem to me that the way to do this is to break the trip, i.e., do part of the RTW trip and then find a (reasonably) cheap ticket back home and then go back later in the year to finish the trip. Very few people (we don't) have the time to be able to do a complete RTW trip in one go. Depending on where you're going and when, a coach ticket (hopefully upgradable in some fashion) from/to LHR or NRT or somewhere similar to back home shouldn't be too expensive and let's you break up the trip.