Portable Saturn?

it's not exactly smaller and not portable either unless you want to call driving it around in your car portable.
The Navi GPS Saturn is actually a Hi Saturn (about as big as your everyday Saturn), with a GPS+LCD add-on plugged in, and some other wares around it.

Impressive? Yes, but not compact. Unless you carry it, and a car battery, in a big bag.

One could re-build the Saturn into a smaller set, maybe using diferent, smaller, parts, but that would be insanely hard.
I kind of doubt anyone would (Tec Toy, maybe?), but it should be possible to shrink down the Saturn quite a bit with modern manufacturing processes and components; apparently Hitachi wasn't exactly using leading-edge processes for the SuperH series at the time (the SH-3 was supposedly done with a 0.5-micron process). This might already have been done for the Hi-Saturn and/or V-Saturn to some extent, but I haven't seen them so I wouldn't know.
You know, that would be a great idea for someone to attempt, I mean, I would DEFINETLY try it, if it wasn't for the problem of me being a rookie at such things (I fix Saturns for the swap meth and 50 60 switch them for people who pay me, but I test everything on my saturn first, and I have a problem, but that post will come later) and me only having £10 to my name, I doubt I could.