I do not currently think trustless lending for USD or a stablecoin is possible on bitcoin. How do you plan to accomplish it?
I will note that Tony Klausing's "stable channels" project lets you opt into a USD "hedging" strategy on bitcoin where your counterparty can't steal your money, but they can just stop participating in the contract at any time. Since hedging is a form of "shorting," the other side of the trade is essentially "going long" on bitcoin, which is equivalent to taking out a USD-based loan and buying bitcoin with it.
I think it would be possible with USDT on Liquid and a cross chain swap, however, my proposal above is something different. You would borrow bitcoin against bitcoin. This can be done purely onchain and in a trustless manner.
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Oh I see. Yes, this sounds similar to my loan shark project: