No----"rolling release" only means that things are updated as they are made available. Arch, for example, could sit on the latest GIMP for 2 months and then put it on their repos. That is still rolling release.

PCLinuxOs is a "rolling release".

PCLINUXOS is a rolling distribution. I'm surprised no one has mentioned it as it has been the top of Distrowatch several times.

Try it out; it's the distro-hopper stopper.

I believe PCLinuxOS is a rolling release.

yes and no. When it went from .93 to the next release everyone had to reinstall, because of the new gcc.

There will always be delays getting new versions of packages into a distribution, because it takes time and effort to prepare the packages and test them. Sometimes there will also be a need to rebuild packages if incompatible library changes occur. GCC is an extreme case because every application that is written in C++ uses a library from GCC, so when that changed a lot of packages had to be rebuilt.

Whether these rebuilds and updates require a re-installation or not depends on the inventiveness of the distribution. Gentoo doesn't make you re-install, but will require you to rebuild existing packages broken by upgrades (tools are there to automate this, but it still takes time and CPU cycles). This was still true for GCC 3.3->3.4, but a lot of packages needed updating.

The other question it is relevant to ask if you want to stay up to date with upstream is how easy it is to create your own package of the latest release of an application from the most recent one in the distribution. Because Gentoo builds from source on your machine, new packages are easy to create and install. Slackware is reasonably easy to do so, but removing that package afterwards may be difficult, so in the end your system becomes hard to manage because of files which you don't know where they came from.

Gentoo seems to be good on the last point - I've had my 32-bit install for over 5 years now, and it still updates fine, no conflicts and the applications work reliably. The main thing is not to try and short-circuit the package management by using make install to add things which aren't available, especially libraries. If you roll a package for them instead (which isn't hard most of the time) then you will be able to uninstall them and replace them with the distribution versions when they catch up with you.

actually a rolling release means, upgrade to the latest version without reinstalling (on the fly upgrading).
E.g. no need to download another .iso file or install discs, to upgrade, just download the files like a normal update would be. (upgrading while the system is still running)