About the only compact I know that could sustain some serious loader work is probably the Fiat 35-66. Arguably one of the best compact tractors ever made.
One of the best things about this tractor is that it has planetary final drives on both front and rear axles. This axle design can handle some serious abuse.
I don't think these ever made to US though.
On the other hand, if the OP is looking for an heavy duty tractor just because of loader work, might as well just get a machine that was actually built to be a loader.
Those smaller articulated wheel loaders, like those Avant, Giant, MultiOne and other makes, are designed and built to be a loader. Can handle all the abuse you can put on those. Offer faster and smooth hydraulics with a lot more reach using the telescoping boom.
More expensive than a tractor? Sure but then again, it's built to be a loader.
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