Hi Guys,
In the rule book there is NO rule even suggesting that you can't stack/overlap ships, in fact it is mentioned that you can go over under other ships and even planets. If overlapping isn't allowed it would be strange not to mention such an important limitation and offer methods of moving ships with this restraint. E.g. add/remove speed not to end with bases overlapping.
Take this with humor Ray, but there's also no rule saying I can't get the metal Kroot sphere and whack someone on the head with it. If the rule is available then point it out. Otherwise, it is not and that...
This isn't a rule invention or crazy assumption.
...Yes, you ARE assuming seeing as you cannot point out an explicit rule.
I'm trying to prevent (friendly) overlapping, I'm not going to drop the issue. It's odd that you'd ask me to drop it since you obviously aren't a fan of overlapping. 
No Ray, I'm not asking you to simply drop it. I've even given a couple of reasons why you should. That's not just simply asking you to drop the issue. Unless you can provide us with a solid, beneficial-to-the-game reason WHY Overlapping SHOULD be in the game, especially your version, you will not get any support from us naysayers or change our minds.
You maybe a fan of area denial, preventing ships from boarding and for slow ships like the Emperor or Explorer turning due to lack of speed, but I’m not. This is unreasonable and unrealistic (as these things go).
Huh! So increase the speed of the Emperor or Explorer. Will you? No, I don't think so. Fluffwise, will you even try to board a ship knowing there is a bigger ship out there waiting to pound you? No, you wouldn't. You want to be able to board ships, fine, change the rule to say if a ship is within 5cm or the target, you may initiate boarding even if the ship has shields up. Simple is it not? Much better than allowing overlapping bases both in rules and actual gameplay.
Can anyone think of any other exploits you could use if you couldn’t end movement overlapping an enemy ship?
Yes. I shoot at the enemy ship. I knock down the shields. I do a H&R attack. I send my AC and/or torps and attack the blocked ship, AC avoiding the blocking base and torps shooting through the blocking base. Yes, there are many exploits I can use to get at the ship being blocked physically by another base. See Ray? I have other options to use than Boarding which may actually even
hurt my ships.
Prevent boarding, preventing full movement, prevent turning of slow ships, forcing extra movement to hit ordy/asteroids etc, forcing a ship to turn. Note: 2 escorts can force a ship to move 12cm straight forward (or have to make a turn) if it has a small base, if the ship had a large base it would be considerably further.
Preventing full movement? Again borrow the rule from another system and move the bases around which causes the least disturbance. it's not going to be that much of a big deal. Aside from which, the base does not prevent full movement, rather it can be bothersome to position the place where the ship ends. It does not prevent a ship from turning. You can turn anywhere along the line of movement and move on from there as long as you meet the minimum movement requirements.
Herding ships is ridiculous, hence why I’m for overlapping of enemy ships!
Sorry but if you are allowing enemy ships to overlap their bases then too bad, you allow friendly ships overlap as well. Fair is fair. Ridiculous is not a game term nor is it a suitable and valid enough reason. Otherwise, if you allow this, then I find your insistence on allowing overlapping bases ridiculous in the first place.
On the other hand, I wouldn't mind people putting a marker on the base and measuring from there. This is to avoid my problem about physically damaging the ships. But don't call it overlapping bases as people will assume you can literally overlap bases by stacking bases which will then realistically cause damage. Call it something else. placemarker or something. This way you can even discard the idea of friendly ships not allowing overlapping.
Maybe this is the issue here. What do you really mean by Overlapping, Ray? I (as in me, I do not know about the others) read it as you really want us to put our models on another model's base which I can tell you right now I do not approve of and I am pretty sure my opponent will not agree to as well since it realistically will cause damage. If you mean that a ship can exist at the same point in time on the table, then my last suggestion should have merit in application. Best to use markers and measure from that point.