I am imagining you have already done a google search, and come up with the same results as me...... NOTHING!...
So, website-wise, I think your out of luck... Maybe some one around here will have one.... You have to just keep checking this thread...
I have never heard anyone talking about the X-26 around here, so I am not sure.
My manual was sold with the unit when I sold it way back in '92
Anyways.. Good Luck.
I do suggest you follow Bruces suggestion and get in touch with fostex and buy a manual.
Joe