I've no idea if this will work for other non-Atheros chip, but if you've a wireless router with the Atheros chip, feel free to get into the bleeding edge. Installation was surely not a straight forward, the trunk/bleeding edge releases are usually without Luci (GUI) preinstalled. You've two choices, one is to download the system upgradable release (sysupgrade) and flash your router from the web interface. All you configuration files will be intact if you go by this route, this includes the WAN and LAN interfaces. What you need to do is just to install Luci from opkg. But for those who're 'stupid' enough to go the hard way (as I've chosen to do), you need to download the packages upfront into your local server and point the opkg configuration to retrive the packages from your local server instead.
How to get Unifi working? Well, in the new Luci interface (yes, the Luci interface is much nicer too compared to the stable release), there is a Switch tab under the Network configuration page. This is where you configure the VLAN tagging and VLAN to port assignment.
Here is the sample of the page (yup, this is not mine.. someone has done this before, why reinvent the wheel :)..
Note: I'm not taking any credit on this .. all thanks to the guy who posted this in lowyat forum as per the link above.