Saw one of these today at a sustainable living display day at Parramatta Lake Park.
The guy had his own personal car displayed with a parallel system running off a custom alloy tank in the boot of about 30-40 litres I'd guess, which fit inbetween the rear wheel arches, and went about 2/3rd's of the way to the boot height, meaning that he could still use his folding rear seats.
He mentioned that the higher flash point of the biodiesel meant that he had to start and stop whilst running on conventional diesel, but once warm, the engine was switched manually to the bio supply.
I didn't get to ask him what engine mods he might have required - but there was a fair bit of extra plumbing under the bonnet, including a 70W pre-heater for the Bio supply line.
He wasn't a Pug nut, but rather a biodiesel nut. He'd be interesting to get along to a club night as a guest speaker - I might send an email to the club about him.
Anyone else seen any other conversions like this?