ZK-REX4 above was built by Rex and Ruth Newman at Omaka and was first registered on 15-07-2004 after some 1900 hours of labour. This is a Vans RV7A c/n 71200 and is one of three built by Rex. This was re-registered as ZK-RFX on the 26-05-2009.
The second edition became ZK-MIS and was registered by Rex on 19-10-2007 before being relisted to The COD Impact Trust on 09-01-2008.
Rex now has a third such aircraft almost ready to roll out. My guess being that this will become ZK-REX5 in the very near future.
[As a matter of interest: If a registration has been issued several times, I add a number to indicate which allocation we are discussing. In the case above we are talking about ZK-REX issues number 4 and maybe 5].
To help complete the picture:-
ZK-REX1 was a Cessna 310B [c/n 310B-35654] from 1958 until 1959.
ZK-REX2 was a Embraer 110P2 Bandeirante [c/n 110-184] between 1989 and 1996.
ZK-REX3 was a Embraer 110P1 Bandeirante [c/n 110407] between 1996 and 1999.
ZK-REX4 was Vans RV7A [c/n 71200] as above.