I always thought the undercut of Excelsior was rather extreme. Instead of just proposing a small drop ship goes there in the small cut out, imagine if a "Complete Excelsior secondary hul was shaped like the Oberth/Grisson. Continue the curve of the secondary hull up just under the tail, terminating just below the aft torp tubes.
This long smooth pod could invert and land, looking like a curvy wedge on the ground.
BTW: Nice drawings of Excelsior here: