Doesnt answer your question of the lifetime for various models but most NUCs can be bought with passive cooling using chassis such as these:
Akasa Newton X
http://www.akasa.com.tw/search.php?seed=A-NUC09-A1B
ABEL H22
NUC Systems - ABEL H22 Series - Tranquil PC Limited Store
I use a Newton X successfully myself with a D54250WYK.