Worked for me. Considering how the HN effect hasn't brought down this service I wonder if they pregenerated the ISO images. Realistically, you could do that for all the basic combinations of user selections since there are relatively few of them and then patch in the advanced customizations at download time if needed. (Although mkisofs is pretty cheap to run, so depending on your platform you could probably get away with no pregeneration.)

It's also interesting to see a distribution offer Razor-qt as the default desktop -- I'm looking forward to what comes out of Razor-qt's collaboration (merger) with LXDE.

A few similar services:

* Slax (a Slackware-based live CD Linux distribution) offers a build service where you can select individual packages (http://old.slax.org/build.php). I'm not sure if it has been deprecated for good with the new version of Slax being developed but it still works. Edit: From how it works it looks like Porteus was forked from Slax. I can't access their website proper right now but googling around confirms this.

* SUSE Studio (http://susestudio.com/) generates highly customizable live media images and VMs of openSUSE. Their gallery (http://susestudio.com/browse) is a nice feature. It requires registration.

Edit: I mistakingly wrote that Razor-qt is merging with XFCE rather than LXDE. Fixed.

Edit 2: While it's not strong evidence their download links (i.e., http://build.porteus.org/dl/$HASH/Porteus-RAZOR-v2.1-(i486|x...) suggest they don't pregenerate ISOs but they may cache them.