No I've got one if these
http://www.sailandtrail.co.uk/lpg-equipment/gas-it-horizontal-lpg-vapour-tank.html
If you look on the site they have standard looking bottles that you have a proper filler point for. I haven't got my filler point in the side of the van, I have mounted it just inside the side door.
I see Reach2Clean also mounted the filler inside the sliding side door.
When I was in the motor trade, selling an lpg conversion meant fitting the lpg filler outside the vehicle. So it was mounted in the body apnel, on the rear towbar or onto the rear bumper. It was against the law to have a filler inside the cargo/cabin area.
I would imagine the same would apply to vapour tank installation.
Added; apparently the rules only apply to standard gas tanks and not vapour tanks that would be fitted to motorhomes for cooking etc. The industry have tried to make their own code of practice - can't find anything about positioning of filler connectors.
However, that may not help you when you fill up at a LPG pump.
As I stated before, we have two LPG outlets near us. Morrisons won't entertain any system that doesn't have an external body mounted filler connector. The Jet garage closer to us is an issue. It seems to depend who is on duty at the time from what I can gather.
I like the idea of an underfloor mounted tank, but this new code of practice discourages fitting them this way as they are open to damage and accelerated corrosion.