Well, I personally don't know of any light that uses larger than standard AAs and still is considered "tactical". Remember, one size bigger means C-cells and they are really fat! A light the size of a 2C Mag is, in my point of view, too bulky to regard it as a tactical light. This, apart from the fact it isn't bright enough to be "tactical".
I think the ONE-cell CR123 lights might suit your needs. When using batteries from decent manufacturers (like SureFire, Sanyo, Panasonic, Energizer, Duracell) you are very safe.
Exploding of CR123s is mostly caused by cell imbalance. And since there's only ONE cell in a single cell light, there's no imbalance too
I have a Surefire L1 Lumamax. This is a two-stage light, with a twisty tailcap and a very easy user-interface. Press the button lightly, and the first stage of 10 Lumens is engaged. Press it down further, and the full 65 Lumens are coming out. As anything above 50 Lumens is considered "tactical" this one suits your needs I think.
The light output is a narrow beam with little spill. This is very useful for inspection purposes, but is useless when you want to light up a broad area (such as in the woods, here you need more of a floody beam pattern). This is something to pay great attention to, otherwise you may end up with an unusable light for the task given.
Here you find more info on this light:
http://www.surefire.com/L1-LumaMax
It has absolutely NO flicker. I am quite sensitive to this, my Wolf Eyes MC-E light has quite a lot of flicker in any mode except for the brightest one.
Do you need a single cell light with more of a floody beam? Then the Fenix P2D might suit your needs. Take a look at it here:
https://www.fenix-store.com/product_info.php?cPath=22&products_id=361
And as this is the incan-forum, I want to end with a very good, very small one from Surefire: the E1E! This single-cell light is not very bright by modern standards (15 Lumens) but can be upgraded using an RCR123 and a Lumens Factory lamp.
http://www.surefire.com/E1E-Executive-Elite (the light itself)
http://www.lumensfactory.com/e_series_specification.htm (the EO-E1R)
The EO-E1R will give you about half an hour of runtime when used with an AW RCR123 cell.
Remember that the 90 Lumens it gives according to Lumens Factory is measured in a different way than Surefire does.
Lumens Factory measures maximum bulb lumens in a photometric sphere, SureFire states "out-of-the-front" Lumens. This can make up a difference of nearly a factor 2.
A way to compare brightness is to compare current draw of the lamps. A P90 Surefire lamp assembly draws 1.15A and gives 105 Lumens according to Surefire. An SR-9 from Lumens Factory draws a comparable 1.22 amps, but is- according to Lumens Factory - 220 Lumens. This difference is due to the different measuring methods.
I hope you have a little bit more useful info now. I hope to help you, not to confuse you, although I may have given quite some new info here....
Timmo.