Very informed questioning my friend....
The DV unit most def is not coming w/ adapter. A single ego adapter allows a flush mount for a large diameter tank (ie AGA-T2, Terminator (Oddy Clone), if the gold top cap is removed. Really this is a shorter and more flush setup than the Rainbow adapter provides. The DV unit is also the 1st edition, so no serial number, a steel battery spring, and a floating positive post. I never use the battery spring, it's just resistance I don't need in a telescoping device.
That said the floating pin is an interestingly dangerous little bit. If you telescope down hard enough it can poke your atty in a not good way. I modded mine, actually made a wood insulator with a brass female insert, and machined a 6/32 brass screw for the post. This made a telescoping & reversible center post. This was a design I made to work with my Terminator atties that have GGTS bases from Imeo that allow a native GGTS type connection instead of the lame 510 stack. Otherwise we identified the diameter of brass rod you can get at any HW store to cut your own Posi Pin and use w/o modifying the MKB. Not in my head now but find the big MKB thread, it's near the beginning. Basically if you cut your own posi pins you can make a custom length that won't poke your atty.
AND THE SWITCH is a big issue, that has a very easy fix. The switch totally blows at first, but again with the HW store visit, obtain a thin brass sheet, cut a rectangle, roll it into the switch body and now it kicks like a mule. A $5 switch becomes a $25 one. Again this is described in more detail in this thread:
http://www.e-cigarette-forum.com/forum/apv-discussion/401929-mkb-ts-mechanical-mod-ggts-clone.html
It may sound a little daunting all this modding, but honestly it's easy stuff and it transforms this almost-a-dud into a very solid rocker. I double team my modded MKB with a genuine GG all day every day. I even use my MKB's collector tank on my GG, since I got only a GG Stealth. A genuine GG collector tank is >$100.
So really I think you should check out the thread I mentioned.... despite it's ever growing length.
The switch shim is actually my silent claim to fame on ECF since I came up with the idea in the first place because of troubles with my MKB switch burning my finger. But now some people are shimming switches on other mods too and loving the results. The brass sheet will bridge the steel springs in most of the China mods with a lower resistance path, and the brass is smooth so it improves the switch action A LOT.
To answer some of your other questions directly...
The GG switch does not directly work, and besides they're very hard to find. If you shim you won't go wanting. However a member here re-tapped his MKB to fit a Ghost Modder sw. that uses GG spec. So we have the tap dimension is you wanted to go there, but I see no reason. The GG sw isn't anything special really.
If you plan on using a Terminator Oddy clone or a genuine Oddy the MKB is a no-brainer to get, but you will want the GGTS Oddy bases. E-smoke Guru had them a few weeks back, so check that out. That would be the first genuine GG item I would seek out to upgrade the MKB.
Really it's the top half of the MKB that has GG threads. The lower portion (teletube, bottom tube) differ from the GG. This is how they work around copying someone's intellectual property. Buying the MKB was a moral dilemma for me. In the end I had only a broken PV, and on that day I could not buy a GG so I got an MKB to hold me over, but it's surpassed my expectations, and a lot of ECF'rs are having a blast with the MKB.
