My widest 8x10 lens is a 159mm f12.5 Wollensak Extreme WA. A really fine lens that I got on Ebay for a steal (less than $200). Mine is apparently a late model because it is coated. These lenses (of various vintages) come up on Ebay quite often. It covers 8x10 easily.
Thanks all, I am looking on e bay also. Hopefully I will find something....
A friend no longer uses 8x10 but while he was in the undergraduate program at Rhode Island School of Design, he did. Sorta street shooting with a Deardorff. One of the lenses he used the most was 6 and half inch Dagor. It covered 8x10. I am on the look out for one of those.