Does anyone know a good unofficial xbox live adaptor which works?

The proper term you are looking for is a “wireless adapter” as you are trying to get on the Internet, this will help your googling instead of using “xbox live adaptor”.

You have two options. You can buy a Wi-fi adapter for the Xbox, or you can buy a really long ethernet cord and connect it to your modem.

That or you can roll your own if you have an extra modem laying around. This is actually a neat solution because you bring your internet to wherever your entertainment system is, in case any other device needs internet and doesn’t have built in wi-fi.

I would not recommend third party adapters. I have had bad luck with them in the past, though not specifically wi-fi adapters. But it’s tainted my opinion enough that unless I really really need the item, I won’t buy third party items, and even then I will read the reviews very closely.

Techincally, you can just buy two wireless routers, install dd-wrt on both of them, and then set one as an “extender” that is receiving data from your xbox and sending it to your other router. I saw some post about it on lifehacker before, but it wasn’t actually for this cause. It would work though. I also highly recommend looking into Ethernet over Power adapters, as I personally use them to great extent.