Maybe you can change the issue with short loans (1 day, 7 days) in such a way that if I lend for X days, I get my money back in max. X * 24 + 24 hours? This would mean I offer a loan for 1 day on Monday 00:00. The whole Monday someone can take of that loan and use it until Tuesday. Earliest Tuesday 00:00 and latest Wednesday 00:00 I get the money back and available in my account.
I think that reasoning makes some sense (in my head it does) - and it allows also 1 day loans. After all, I WANT to loan out that money, but I might need it back quickly (or to give out another loan). In the end you'd add a 24 hour buffer "in front" of the loan period to take up the loan.
I see a few different scenarios possible then:
The loan offer is taken within these 24 hours and ends X days later, then gets reposted or not.
The loan offer is not taken within these 24 hours. Then (if I didn't want to repost, because I might need the money after X days) I'd like an option to automatically reduce the offer by 1 day and be reposted (e.g. 7 days on Monday --> 6 days on Tuesday etc.).
This is a common complaint. If a user requests a loan for 7 days (as an example) and then goes to use it 1 minute later, they can't select 7 days on the trading screen. While technically correct, this defies common sense. The simpliest solution would be just to covertly add a few hours to the loan length on loan offers such that a lender offer of 7 days is technically 7 days and 3 hours, a borrower request of 1 day is really 27 hours, and so on. I think doing so would end most of these complaints with very minimal programming changes.