Engine Power Weight Kg/hp TBO
------------------------------------------------------
Hirth H30ES (2g-a) 102hp 42kg 0.42 1000h
Masquito M2.6 (4g-a) 120hp +50kg 0.41 1000h ?
Rotax 914UL (4tg-l) 100hp 74kg 0.74 1500h ?
DAIR-100 (2td-l) 100hp 93kg 0.93 2000h ?
Zoche 01A (2td-l) 150hp 84kg 0.56 2000h ?
Deltahawk V-4 (2td-l) 160hp 148kg 0.92 2000h ?
SMA MR 200 (4td-a) 200hp 129kg 0.65 3000h ?
Centurion 1.7 (4td-l) 135hp 134kg 0.99 2400TBR ?
Lycoming IO-360 (4g-l) 200hp 135kg 0.68 2000h
Continental CSD 283 (2td-l) 200hp 136kg 0.68 3000h TBR
Junkers Jumo 205 (2td-l) 0.69
Williams EJ22 (f) 38kg

2 = 2-stroke
4 = 4-stroke
g = gasoline
d = diesel
t = turbo and/or supercharged
a = air cooled
f = turbofran turbine engine
l = liquid cooled

In my humble opinion, the most promising seem to be Continental CSD 283
(the Nasa GAP engine), SMA MR 200 (Renault Morane) and last, but not
the least, Zoche. On the other hand, Deltahawk and DAIR seem ready for
production.