Slider or track for bench seat?

[IPT]

Hey guys I am in the planning stages of a build. I have one child (1 y/o) and likely another on the way soon. My goal is really a flexible gear/kid/toy hauler we can camp in and get out of the weather if it gets nasty.

Since I am going to want to sleep 4, I am tall (6’3) and because I want the ultimate flexibility I think a penthouse will be the way to go (seems like CCV gets good reviews for its size, ability to insulate, and it’s strength (better stability on wind?).

The real issue is the bench seat. Will need one for kid seats and to convert to a bed for lower level sleeping. However to make the most use of the space it would be ideal if I could move it forward to the original position for driving, then slide it back once at the destination to make the most of the floor space and open top.

I don’t own a van yet, but I am leaning toward the 4x4 sprinter. Seems to me shouldn’t be that hard to have someone fabricate a seat slide for this (or is there one available?). We will likely start with a passenger van so we could use the bolt placements for the front and rear bench seats for solid anchors.
Anyone have insight or experience with this? I saw one youtube video of a guy who used some VW slide. He ordered stuff from overseas though and had to do a lot of fabrication under the van for secure mounts. Hoping to not have to go that extreme!