  We report on the discovery of the shortest period binary comprising a hot
subdwarf star (CD-30 11223, GALEX J1411-3053) and a massive unseen companion.
Photometric data from the All Sky Automated Survey show ellipsoidal variations
of the hot subdwarf primary and spectroscopic series revealed an orbital period
of 70.5 minutes. The large velocity amplitude suggests the presence of a
massive white dwarf in the system (M_2/M_sun > 0.77) assuming a canonical mass
for the hot subdwarf (0.48 M_sun), although a white dwarf mass as low as 0.75
M_sun is allowable by postulating a subdwarf mass as low as 0.44 M_sun. The
amplitude of ellipsoidal variations and a high rotation velocity imposed a
high-inclination to the system (i > 68 deg) and, possibly, observable secondary
transits (i > 74 deg). At the lowest permissible inclination and assuming a
subdwarf mass of ~0.48 M_sun, the total mass of the system reaches the
Chandrasekhar mass limit at 1.35 M_sun and would exceed it for a subdwarf mass
above 0.48 M_sun. The system should be considered, like its sibling KPD
1930+2752, a candidate progenitor for a Type Ia supernova. The system should
become semi-detached and initiate mass transfer within ~30 Myr.
