I sympathize, I remember their DNS going down a couple times years ago, much more with another ISP but oh well. It really kills the internet, doesn't it?
Lots of options. You could go the full way and set up a caching DNS server with BIND or djbdns, DJB's is (probably, or just historically) more secure and lightweight but BIND is more the standard...I go with BIND as DJB's was missing a feature you probably need. iCab has a DNS caching feature, can just turn that on and gloss over small DNS outages. You could get your common sites' IP addresses from other people or when your DNS is up, and map those in your hosts file. You could get the IP of a website that does lookups, I did for a while at home which was useful enough. Finally, you could pay for a DNS server, not terribly expensive but it's an unnecessary cost....better to yell at Telus.
I'm afraid I can't help with the one you're trying to figure out, but it sounds like you're reinventing the hosts file (which I know you know of)...chattr +i seems to lock the file on a linux partition (hence why it's not in OS X)....but the resolv.conf file lists DNS servers....
edit: from the resolv.conf man file-
"To define a domain host that is not a name server, enter:
domain abc.aus.century.com
nameserver 192.9.201.1
nameserver 192.9.201.2"