[TriLUG] DNS question: CNAMEs at second level

[Brian via TriLUG]

Hi folks,

I've recently learned that CNAMEs at second-level are forbidden (e.g. 
undecidedgames.net can't [read: shouldn't] be a CNAME).  Unfortunately, 
that is my domain and that's exactly what it is, a CNAME to my dynip 
domain.  Back when I first bought it from 1and1, they allowed 
second-level domains to be configured as CNAMEs.

Well, it still works, but now I know it's a violation of standards, so I 
want to make it right.  Thing is, having it act like a CNAME is still 
exactly what I need.

Is there a right way to have a second-level domain act like a CNAME?  My 
IP isn't horribly dynamic, but it isn't static and does change every few 
months or so.  I know of no way to update 1and1 A records without using 
their web interface (so I can't just have an A record that my server 
automatically updates as it does for the dynip domain).

Short of buying DNS service from somewhere that will allow such remote 
management (or shelling out for an honest-to-goodness static IP), what 
can I do?

Thanks,
-Brian