Is it possible to enter some sort of CNAME record or alias in the windows hosts file (C:\Windows\System32\drivers\etc\hosts)?
Basically I want to forward all requests made to host A to host B, without having to hard code the IP address (which changes frequently).
The windows hosts file supports only ip->name mappings, it does not support any other standard DNS record types. See here:
http://technet.microsoft.com/en-us/library/bb727005.aspx#EDAA
I would recommend running a simple dns server in order to do the redirect you are talking about. Try powerdns http://www.powerdns.com/
PowerDNS is not supported on Windows. I would recommend a tool such as "SimpleDNS" (14 day Trial) or "Technitium DNS Server" (free) which can be used to create a simple local DNS server.
Once you setup the program, you can create a zone and record for the CNAME you're trying to test and point your DNS server settings to 127.0.0.1 only to test.
I was able to use this to test TrafficManager and this looks to be the easiest way to do it on a Windows computer.