The Kubota loader for the M6800 is the LA1162. The quick attach coupler is a $650 option according to this information.
STATE OF MINNESOTA
I am surprised it can't be just ordered with the quick coupler rather than the standard pin on.
Actually the FEL for my M6800 with standard transmission is the LA1002 not the LA1162 which Kubota tells me is only for the wet clutch hydraulic version which I don't have. You are right in that the LA1162 come standard with universal skid steer coupler, but that option is not available on the LA1002. My dealer is hesitant to order a 1162 bucket for my 1002 even though I feel it would work fine with the Tach-All QA I am ordering. No where can I find a part # for just the Universal Skid Steer Kubota bucket, which I agree seems the logical choice. My dealer is not much help as they know nothing about this Tach-ALL although it was recommended by Kubota's national website. Rather than arguing with my dealer or trying to convince them the 1162 bucket would work, I thought it safer to just order an aftermarket one that clearly states is "universal skid steer compatible." I'm pretty sure it would work fine, but if not, my dealer doesn't seem willing to accept that risk. I guess I could ask Kubota's national customer service center this question. I really think the LA1162 loader itself would work fine ( and save me the cost of a Tach-All) but again my reply from Kubota's national site says that "although the LA1162 will mount on a M6800 SD, it is not approved because.... of the lack of a wet clutch for heavier applications." Hence if used without approval, there would be warranty issues I expect.