When i think of infinite records one thing that comes to mind is
Gescom- Keynell SKA007
It doesnt do the magical loopback but the run-out groove is looped so
that it keeps playing sounds that sound similar to sounds from the last
song on the side, effectively making the songs sound somewhat infinite.
not sure how many other records do that..but this is the only one i have
that does.
my 2 cents.