for some reason checkinstall isn't in testing, I was wandering why and when I can expect it to return.

Why?
As of this page, it seems like it was removed from testing due to a grave bug that could lead to filesystem corruption.
This has now been corrected since February 2006. Unfortunatly since this time, this package has not gone under the threshold to be accepted again in testing, so it stayed in unstable for more testing, while the previous stable sarge version could still be used.
On the 7 of december, a new release candidate appeared. Unfortunatly 4 days after testing entered in frozen state, 10 days are required for a package to enter in testing, without more RC-bugs than the previous testing version.
If the package (in previous version then) was without new bugs, then it should have entered
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=367966

Try the unstable version?

Well that explains the why. I hope they make an exception and add it to etch, checkinstall is IMO a vital package. That said I don't need it now, and I plan to try sticking with testing rather than staying with etch so unless I need it soon I'll probably just wait for it to migrate to testing post-etch.