> from the problem of the band not being remembered by many people under 25, there's the
> designs they had back in late 80s and early 90s.  Fine for that time, but now as dated as
 
I wouldn't say they're dated.  80s retro t's are kind of popular now (I just picked up a vintage style Devo shirt a few weeks back).  And, at least here in the States, you're not going to find many that have heard of the KLF (until reminded of 3am's aha-aha hook).  I used to get a lot of compliments on my KLF T speaker logo'd shirt back in day from people who just thought it was a cool design.
 
-paul