You don't mention whether you have plenty of time to spend on the conversion.
But if you do, then one of the lightest and cheapest ways of fitting out a van
interior is to construct in a timber and ply panel face method. The ply
only needs to be 3.76mm (nominally 4mm) 8 x 4 sheets with single face
veneer if you want a timber finish, or just low grade if you cover with
the ubiquitous glued polyprop. carpet liner. The frames softwood 40x18mm
The ply can be knife cut along a steel straight edge. Door frames faced both
sides of the frame to give rigidity, finished with simple mouldings mitred
A few pics to give you the idea.
i don't know.. I have had both FB and non FB before.. but that was a long time ago and not relevant as neither vehicle (tiny british and large armerican - campers) went very far..
I miss another place to sit, with a decent table.. but I really like the bed always there and no fuss.. if I had to change that part of van it wouldn't be that tough.. I will leave it for now and do some more trips ..
Doubt if you want to be close to, let alone 3.5t in a Vivaro
I used IKEA units in my LWB T5, so a similar sized vehicle
I had 7 cupboards with a total run length of 4.2M as well as as quite a few sheets of standard Ply sheet as bases and tops and IIRC the whole vehicle weighed in at around 2.3t including fuel and all camping gear, so plenty of payload left over (mine is a 3.0t GVW)
We bought a van with a fixed bed and I thought the same and we had plans to change it. I was wrong, very wrong. We realized very quickly that it was brilliant and would definitely not change it. We have adapted the storage under the bed to suit us and it has meant we can keep the living bit of the van uncluttered. I went away with my brother the other week and I thought never in a million years would all that moving stuff around and the whole space being taken up by the bed suit me now.
With our p.v.c we have a rear lounge, with a back bulkhead to give vertical storage in the back, this eliminates the leakage/draughs from the back doors.
We can the sit with our feet up on each side of the van, this then turns into the bed.