Can I get a 90-day L-visa in Hong Kong?

Hello. I'm from the United States and I am just about to finish a year of teaching English on mainland China. I want to travel for about ten weeks after I finish teaching, but my residence permit expires on July 14th. I looked into applying for an L type in China (to be done during the last two weeks of my residence permit) and was dismayed to find that if I apply on the mainland, I can only get an L for 30 days, at the cost of around 940 RMB. My new plan was to travel to Hong Kong as my residence permit expires to apply for an L (single-entry). My understanding was that if I apply in Hong Kong, I can get an L with a duration of 90 days, presumably at the equivalent of 940 RMB. However I've read mixed things about the possibility of attaining a 90-day one. Some sources say I can only get a 30-day one, which I then have to renew (also at the cost of 940 RMB per extension). If all my options can only lead to 30-day visas, I don't want to go all the way down to Hong Kong, but if I can get a 90-day duration, I'd much rather do that than pay 940 RMB multiple times. Any information that anyone can provide will be very much appreciated! Thank you for your help!