You can get large twin axle caravans, German makes like Hobby, Wilk, LMC etc known as 'dry' vans with no sink cooker or toilet. Used on permanent travellers sites that have brick outhouses. I imagine you could order a smaller one from the makers.
I have considered it but DIY is not my metier. I would consider someone elses labour of love though - surely I'm not the only one who doesn't want a cramped toilet and kitchen ?
I think you're going to struggle if you aren't willing to make some modifications yourself, have you thought about getting someone else to modify it for you?
Put the names into ebay search, they often come up on there. They would make ideal site vans but too large if you want a tourer tho. If you wanted a smaller 'van converted I guess the place to go would be a campervan converters, a smaller place that builds to order. These sort of companies advertise in the motorhome magazines.
It would seem an easy enough job to remove kitchen & toilet/shower & replace with extra seating. You would need to be very certain of what you wanted tho because for the price of the caravan & the work required you would end up with a caravan with little resale value.