PelicanHPC
v2.3 and above is amd64 only, use v2.2+eps if you need a 32 bit version. You can also make your own
32 bit version quite easily using make_pelican-v*

ParallelKnoppix
The final PK image is available here. It is out of date compared to PelicanHPC, but it has more examples.
There is also an older PK image that has parallel povray.