Hi mutationtarot
Depending on how non-standard, you may want to look at finding a printer locally who can cut your cards to the size you want. If you contact some of the printing companies (who specialise in cards... makeplayingcards, superiorpod, TGC etc), they may be able to quote for custom/odd sizes, though I am guessing this would mean a (large) minimum qty.
A while back I found this delightful display of differently shaped playing cards:
http://a_pollett.tripod.com/cards19.htm (I know it isn't really helpful in terms of finding a printer, but worth a look
)
*wave*