For those interested in an outsiders view of the world of vegemite - take a look at:
http://www.dallas.net/~jsides/vegemite.html
Personally, vegemite is OK... but promite is just in a different league. Now that is YUMMY.
Kraft Australia says you can order it in the US from:
Australian Catalogue Company1800 808 0938
www.aussiecatalog.com
West Bay Sales - Vegemite
351 Rancho Camino
Fallbrook, California
www.ozchannel.com/vegemite
If you're suckered into buying some to try and can't find a use for it you can use it in recipes...
Grilled cheese on toast... spread just a little bit on the bread before you put the cheese on and you'll be in heaven.
Bring a head of cauliflower in a vegetable (or chicken, or veal) stock and cook until tender. Add a good teaspoon (or three) of vegemite/promite/marmite and stir through. Puree and consume with toast. Quick, easy and healthy.
But to answer your questions Chris -->
Can't say I've come across any Vegemite type jerseys. There are a few Australia/Aussie themed ones about... Would you like me to dig up the URLs? I can't point you to any Australian based custom jersey makers, but there's lots around overseas but you're looking at $50USD approx and minimum 10-15 quantity order.
This comes sort of close to Vegemite logo / colours