There haven't been very many made in this scale - 1/35 is usually reserved for military vehicles! That said, Tamiya do currently make a kit version of a Simca 5 staff car which is widely available and there is also a Fiat Topolino (the box says "Italian light civilian car") kit from a Hong Kong model company called Bronco.
http://www.emodels.co.uk/1/32 is the more usual scale for civilian vehicles, but although there have been a few plastic kits in this scale in the past, I don't think there are any currently available. Airfix made the Bond Bug in the 1970's and ARII did a whole series of Japanese microcars
http://www.ratdat.com/?p=295 but all of these went out of production many years back so you'll have to search Ebay for second hand ones. Mind you, the Bond bug kit sells for £150+ nowadays - someone was making a fairly basic resin slot car version of this a few years back, but it looks like it this now unavailable as well.
There is however this Spanish resin slot racing Isetta.
http://lagartijakit.blogspot.com.es/2013/03/bmw-isetta-250-presentacion-y-despiece.htmlAnd even a slot car body for a Messerschmitt TG 500.
http://members.optushome.com.au/pattosplace/sedan.htmlNot brilliant, but better than nothing.
