If 10-year-old game systems make the cut, why not a 15-year-old computer? (Heck, a Quadra 840 may very well be faster for many tasks than a Power Mac 7100/66. I've just found that iCab 2.9.9 on 68k makes many sites that I pretty much need to use unusable; while 2.9.9 on PPC works fine on the same sites.)
edit: Ah, now I see the 486/68040 specification in the rules....