The LT250S is just an LT230S with a 30cc larger engine.
Everything else is basically identical.
So, if the LT250S is any good for a hybrid, the LT230S would be just as suitable.

As far as the front suspension, it's narrower than the 250, but wider than the Z400 on the bottom.
It wouldn't take much effort at all to reposition the lower a-arm tabs and retrofit Z400 a-arms.
Problem is, the 230 frame is pretty weak for its weight...so it would need some reinforcing.
As far as the size of the frame itself, it would be a great if you could get the Z400's wheelbase on a 230 (it would be like having a +6 swingarm and +6 a-arms).
Probably handle like nobody's business.
The other problem is that the engine area is also pretty small, so that limits you in what kind of engines you can run without serious modifications to the frame (think sport bike engine in a zilla modifications).
A 4-stroke thumper engine would be the easiest choice, as you could bend the exhaust to conform a lot easier than you could a 2-stroke pipe.
I've done some preliminary measurements and I believe a Z400 engine could fit without too much work, possibly an LTR with some tank and frame modifications.

That help answer your questions?

I was thinking the same on the RMZ. I've got the DRZ250 in a blaster frame, but its a complete turd.

Its not a DRZ top end. Got a custom twin cam 300 top end on her now. Bumped from 24 hp to a whopping 29. Totally not worth it..

Well, you definitely don't want to modify the 230's engine to put out that kind of power, because it turns into a REAL money pit and performance parts are pretty scarce.
The Z400's engine is a bit tall, you'll have to drop the frame a tad or angle the engine forward more.
I have checked the frame to see if a radiator would fit, and there's also enough room for an oil tank and standard size battery as well.
The LT230E already has a battery box located in front of the grab bar and underneath the seat.
It's all relative to how much time and money you want in an LT230....it'll be a hell of a 230, no doubt it would be fun and great on trails, but you may be better off finding a quad that fits your wife better.
The Z400 is my wife's ride, and she really likes it.
She seems to control it well, especially considering she's only 110lbs.

Sounds like the DRZ may suit her well in the 230. Its a pretty smooth motor, its just really frikkin bulky in the bottom end. No oil tank or radiator needed. They are really tough, the only issue I've had with mine is the starter clutch.

The Z400's engine is a bit tall, you'll have to drop the frame a tad or angle the engine forward more.

I measured again tonight, and I think the z400 engine might just fit in there fairly easily.  It looks tall, but I don't think it's much taller than the factory engine.  The only disclaimer would be the spark plug in the center of the head, and making that clear the center pipe of this chassis.

I got some measurements from the drz250 engine, and it seems like it is just as tall as the z400 engine, but much larger in diameter due to the cooling fins.   I have doubts that it will fit because of the way the gas tank straddles the upper part of the frame.  Unless I wanted to make a custom tank.

Which leads me to the rmz250 engine.  Just by going by pictures on the internet, I suspect this engine will drop in easily.  The only real pain with it would be dealing with the kick starter, as this chassis was not designed to accommodate a rear kicking kickstarter.  But that would probably be easier to deal with than a custom tank.  This option is VERY expensive compared to the others and you have no electric start or reverse.  I'd like to get a height measurement on this engine if anyone has access to one.