Our team has developed Burrow, an online rental booking software in line with AirBnB (AirBnB clone).
Ever since, we're asked to build a better rental booking software, we've thoroughly studied every websites on the domain including: 9flats.com, myfriendshotel.com, crashpadder.com, istopover.com, roomorama.com, metroflats.com, vrbo.com, couchsurfing.org, globalfreeloaders.com, Stay4Free.com, lodjee.com, evergreenclub.com, sublet.com, homeaway.com, onefinestay.com (and, now Wimdu.com)
Though AirBnB was popular and gaining news, we noted that AirBnB's UI is a great pain and it lacked many necessary features available in other similar sites. Our team has thoroughly analyzed the project and applied all necessary knowledge that we gathered from our FPPlatform product (that powers most of the Fiverr alternative sites).
Recently we keep noticing that AirBnB is chasing Burrow's calendar UI, referral concept, flagging option and review rating. Ironically, I think, it would be wise for AirBnB to buy Burrow and save the chasing cost instead!
Burrow's every piece is well architected and designed to scale high traffic sites (with gzip based file caching mechanism)
Here's the comparison document I have prepared sometime ago Burrow Vs AirBnB; note that some comments may be outdated as many new features have been added in Burrow since then.
Burrow can be customized to fit in to similar domains: renting office spaces, renting vehicles, etc