I am considering a 1981 Kubota B7100DT 4WD, serial # 51225, with a nice loader and rear blade. All componets work well, runs strong and it is in very good shape.
I'm not sure what is a fair value but for me I paid $5500 for what the owner claimed was an 86 or 87 B7100DT with FEL. BB and tiller attatchment, 1350 hour. I thought it was a fair deal considering the condition and lack of good deals on the left coast.
Mine is an early one -- had no ROPS when I bought it. A dealer has told me he's give me between 4 and 5k for it on trade. I think I could sell it for $4,000 without too much trouble.
I'm in Canada, but I sold my old 86 B7200DT/FEL, homemade single furrow plow, homemade subsoiler and a homemade 'V' plow for the 3PH for C$8500 a year ago and it had 800 + hours on it.