There are LWB conversions with built-in cassette toilet and a pop-top - I have one
I looked at a Cali but ended up going with a conversion from Jerba. They're one of a handful of UK converters who are registered VW Body Builder partners, which pretty much does away with the fear of "giving someone a VW van to cut the roof off". Here's what I wrote on a similar thread last year about reaching my decision... (btw, I'm not sure if the VED position is now the same as it was for us when we bought in 2018)
"We looked at the Cali but chose to go with a brand new Jerba conversion because several aspects suited our intended use better. We prefer to stay off-grid as much as possible so chose the 4-seat layout with a rear kitchen and onboard cassette toilet - we can comfortably do 3 nights "wild" before we need services for our water and loo, and with a solar panel we virtually never take a hook-up pitch.
We chose a Wallas diesel-powered combined hob/heater, so we have no gas cylinder onboard, and no potential issues with ferries/tunnels or different cylinders in different countries - as long as we have diesel in the vehicle's tank we can cook and keep warm.
We still have 4 beds including a 150kg rated roof bed for 2 adults, and a choice of 2 singles or a double downstairs.
Jerba produce their own elevating roof. The roof canvas is cotton Ventile so it doesn't suffer from condensation, and all the vents are fully proof against Scottish midgies.
There are a lot of other nice little touches. Jerba aren't big on bling (although you can spec it to a fair extent if you really want) but they do produce very practical campervans.
Because the conversion was done on a new T6 window-van it counts as a "2-stage build" and so it's registered from new with DVLA as a "VW Jerba Sanna", body type Motor Caravan, but since the emissions are unknown because the conversion has altered the VW factory figures, it gets a taxation class of Private Light Goods and therefore pays £265 VED per year.
The 3-year VW Warranty is completely unaffected by the conversion (I took the 5 year / 80k miles extended warranty), and there's a 2-year warranty on the Jerba conversion work."
And as I said on that thread, in the end it's all about personal preferences and requirements, and what compromises you can live with. If a Cali feels right then go for it, but if not then good alternatives to get just what you want do exist.