I finally collected my last collar. The yellow collar for the Kennel Playcase. I think I'd been looking for that for at least two years.
http://www.ebay.com/itm/Kenner-Littlest-Pet-Shop-LPS-Yellow-Collar-/121651936946?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=ChRBRj39N71hLwjEnfI%252F1lyqk%252BI%253D&orig_cvip=true&rt=nc