And now returning to the real thing about this post - FE 600 rod !
First thanks bushie for your bearing cattalogs, I've made some surch myself and will send you a couple that I found.
The rod bearing of the 600 is a 30X38X17.8
You can find the same on the NTN - PK 30X38X17.8 X1
You can also find very close ones, that can be fitted with some skill, on:
INA - KZK 30X38X18
IKO - KT303818 EG
NSK - FWF-303818-E
NBS - KZK 30X38X18
WISECO - B1060
As a curious thing, the bearing is not the same, but the needle rollers are the same of the KTM 525, it might come in hand to someone this info.
Hope it can help someone !