What is the maximum storage fee that can be charged if a mobile home has been repossessed but has not been removed from your property yet?

That would be a nice scam, but the reality is, you're the one who has injured the lending institution. If you want, you can save yourself some money and have it towed to the lot of the lending institution's choosing. Call them and ask where they want it, then pay to have it hauled off. You'll pay for it in the long run, after they sell it at mortgage they won't be able to get what it's worth then you'll be billed for the difference plus the fees associated with hauling it away.