For a sub, if you used a vinyl laminate in cherry, I think it would blend fine with the rest of the set, but I am not as picky as you on aesthetics.Shipping is only $99 I think. 5 decent speakers for $600 sounds like a pretty good deal, I'd guess. The veneer is supposed to be real wood.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=261-614&FTR=cherry%20laminate&CFID=11388241&CFTOKEN=33620875
Or you could try to match the set perfectly and use real wood veneer and stain.
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-050
