Sorry for this post.

I found an entry with photos depicting the installation of the Bebob and a DM plate (similar to the VF). Apparently, the Bebob plate fits between the base plate and the base of the camera.
http://img75.imageshack.us/img75/2127/ontripodsideew7.jpg

I have the black VF gadgets base plate and Coco EX battery adapter for my EX3. Although the Coco is really designed for the EX1, it does fit very well in the Ex3. I just bought it in time for my nanoflash. I will take a power feed from the Hirose connector for the nanoflash and still run the camera (of course) from the BP-U60 battery. The slightly odd thing is that the battery is attached to the Coco 'backwards'. No big deal. Works very well.

I have the black VF gadgets base plate and Coco EX battery adapter for my EX3. Although the Coco is really designed for the EX1, it does fit very well in the Ex3. I just bought it in time for my nanoflash. I will take a power feed from the Hirose connector for the nanoflash and still run the camera (of course) from the BP-U60 battery. The slightly odd thing is that the battery is attached to the Coco 'backwards'. No big deal. Works very well.

There is, however, a model that is made for the EX3...see link, but I am concerned about the fact that it is distanced from the back of the camera. In contrast to your powering decision, I intend to use the AB battery to power the camera as well as any eventual accessory, i.e. Nanoflash, thereby, negating the need for the Sony battery. With this in mind, I am wondering whether, for my application, the Anton Bauer QR-EX3 might not be more suitable mount? Of course, the D-tap might require a connector change from the conventional connector but I believe that such is available (Bebob Engineering | COCO-EX3-AB Anton Bauer | BE-COCO-EX3-AB (http://www.bhphotovideo.com/c/product/591418-REG/Bebob_Engineering_BE_COCO_EX3_AB_COCO_EX3_AB_Anton_Bauer_Battery.html))
The above notwithstanding, I assume that Bebob mount that you are using is different than what I have seen (see above link), since it would appear that the EX3 intended version would have to be unscrewed in order to insert and remove the Sony battery and that is, if there is enough clearance behind the Bebob's rear protrusion to allow for the extended portion of the Sony battery in first place.

As I already had some bp-u60 batteries and sold off my v mount batteries and charger, it was great that the coco ex fitted into my ex3. the custom made cocos for the ex3 are limited to v mount and ab batteries as you have mentioned.

my setup is convenient and lightweight, which suits me perfectly. just waiting on the ever improving nanoflash now! best wishes

Ron
I own the DM baseplate which I believe is very similar to the VF Gadgets plate. I also have the Bebob Coco EX3 and it fits wonderfully under the DM plate. No issues whatever on the fit with the two parts.

I would strongly recommend the Coco EX3, as it not only provides two D-taps (one of which is bi-polar so no matter which way your D-tap is wired you can use it by matching the positive and negative pins on the plug diagram) but it also has 4 (count 'em FOUR) hirose power taps. One of those needs to be used to power the camera though, but you still have 3 free hirose taps for wireless or whatever. I have found this battery adapter to be incredibly versatile. I use a v-mount IDX battery which is stackable, and can literally go for a couple days even with wires attached.
Two downsides: one, since the battery mount is off-set to allow access to the connectors on the rear of the camera, the balance is thrown off completely with such a large battery and it's hard to even get the camera to sit on a table without toppling over.
two, the hirose taps are hot all the time there is a battery on it, so whatever is connected to them will not power down with the camera. It's easy to accidentally leave your receivers powered up when shutting the camera down.

Other than that, I am quite happy with the setup. If you do go with the EX3 mount, make sure you get the newer power plug for the camera with the 90-degree tap on the camera end. The old ones stuck out just asking to be snapped off or jammed which would be a disaster since it's the only way to get the camera powered with this configuration.

Ron, I agree with Derek. For your requirements, the Coco EX3 to suit your batteries is the logical choice as was the Coco EX for my specific requirements.

Best.

Thank you both for your input.
That the Bebob offers the greatest level of versatility is undeniable, however, I am concerned about two issues, one of which was already mentioned:
1. The influence upon camera balance as the camera has balance issues of its own.
2. The fact that its installation will represent a more or less permanent attachment.
My style of shooting does not require an on-camera light source and since most of my audio is ported to the camera via an SD 442/Hirose, there is no need for a wireless receiver to be attached to the camera. Furthermore, power for the receiver is contained within the SD 442's carrying case. Therefore, at the current time, I only foresee the potential need for one additional power tap for the possible addition of a NanoFlash. With this in mind, and for my particular needs, the Anton Bauer QR-EX3 might be more workable and less costly solution. My only concern is that the QR-EX3 apparently does not click into place in the EX3's battery compartment and might not represent the securest of attachments. On the other hand, it is easily removable allowing for the quick insertion of a Sony battery if need be.

With that said, if I find that the QR-EX3 does not suit my future needs I can always place an order for the Bebob...nothing is forever.
Thanks again for all your input.