I resorted to eBay (as usual! ;) )
The set of highlighters:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=360200063872
The set of pens:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=360224713826
No shipping charge, which makes the price a little higher than they are at Staples. They came from Hong Kong and took about 9-10 days, if I remember correctly.
I like the highlighters because even on darker fabrics, they leave a discernible line to follow. Great for marking pieces of needle-turn applique.