An example would be:
-Assuming the next difficulty change is to 2.5 million (gives a nice 0.00002 BTC/share at 100%).
User A requests a loan of 10BTC, I grant it, and in return they have to mine at least 526316 shares (10BTC @ 95% PPS) during the next difficulty period to the pool details I specify in advance.
If they overshoot the target, I pay them 0.0000195/share (97.5% PPS) for any shares mined over and above 526316. If they undershoot the target then we negotiate new terms - payback of some of the loan in BTC or further mining following the difficulty retarget.
Would any miners be interested in accessing loans in this way?
I have a very stable 3.3gh/s I'd like to use as collateral on a loan to snag another 7970 immediately if you're interested in making a deal. It would bring me up to 4gh/s, I would need a 30btc loan to make it worth it for me. PPS calculator at deepbit says I'd make 40btc/month at current difficulty running 4gh/s, so a 3 week payback period would be all I would need, maybe a full month depending on price/share and uptime. If mining takes a shit or BFL ships a month early I have cash to buy btc with, I just figured that if I can keep cash out of the equation at this point it would be a good idea.