I bought my
B7500 in September 2000 and have done a lot of work; moved/spread about 750 yards of topsoil, built several stone walls, moved snow in the winter, mow the grass, ...
But. some of the stones were too big, so I needed to rent
L48.
I needed to do some major digging to pull out some very big stumps and dig a long trench in a wet area and therefore rented a tracked KX-121, twice, and a KX-161 once.
If I were to do it again I would have probably gone with the
bx2200 since from now on out that my major work is finished, all I need is a mower to cut 1.5 acres of finished lawn and move snow in the winter.
If I were in your shoes I would get the
BX2200 and rent a KX-121(161) for a day or two to tear down and bury your barn.
I am not expert but I have some good experience using a couple of back-hoes. I STRONGLY do not think the
BX22 or 7500 will do the job. I am assuming your barn is pretty big and thus these two machines will not have the reach to dig a deep enough hole to bury the pieces. Going with the
BX2200 and renting the heavy equipment as you need it, you'll end up with a nice machine to cut your grass in the end, and also get your job done with less money spent in the end.
Good Luck.