how about something like these Whelen products: 
70285
 MODEL 70285 SERIES
FAA-PMA APPROVED
The model 70285 Series is a self-contained Comet Flash strobe anti-collision light. It utilizes the same lens/reflector and strobe tube as the model HRCFA, however, its vibration resistant, heavy-duty construction is specially designed for Helicopter applications. It has a fixed mounting adapter, and an ms input connector. Available in three different Lens colors, Aviation Red, Aviation White, and Split Aviation Red/White. Also available in radio shielded configurations. FAA approved as a direct replacement for any Rotating Beacon that uses a 3-3/4" dia. Mounting hole. Unit will operate between 10 to 30 volts DC.
SPECIFICATIONS: 
Power Consumption:  3.2 Amps @ 14 volts DC 1.2 Amps @ 28 volts DC           
Weight:  1.5 lbs.  Height:  8.0" Diameter:  3.7"      
Drawing Number:  70285             
Model Number:  Part Number:  Description:  
7028521 01-0770285-21 shielded, Red lens 
7028522 01-0770285-22 shielded, Red lens w/.31 mask 
7028523 01-0770285-23 White lens 
7028524 01-0770285-24 Split Red/White lens 
7028525 01-0770285-25 Red lens 
7028526 01-0770285-26 shielded, Red lens w/.29 mask  
7028527 01-0770285-27 White lens, w/lock wire 
7028528 01-0770285-28 shielded, Split Red/White lens 
 
SA,CF
 MODEL SA,CF SERIES
FAA-PMA APPROVED
The model SA,CF Series is a self-contained Comet Flash strobe anti-collision light. It utilizes the same power supply & housing as the model HRCFA. It uses an Aviation White glass lens only, which is ideal for agricultural applications where chemicals are used. Because the lens has no optics built in, it produces 300 effective candlepower. It uses a 3-3/4" dia. Mounting hole. Fuselage installation requires the A440 mounting adapter. Unit will operate between 10 to 30 volts DC.
SPECIFICATIONS: 
Power Consumption:  3.2 Amps @ 14 volts DC 1.2 Amps @ 28 volts DC           
Weight:  1.5 lbs.  Height:  5.50" Diameter:  3.7"      
Drawing Number:  70030             
Model Number:  Part Number:  Description:  
SACF 01-0770030-01 Aviation White lens