From looking at your post, I'm not 100% sure exactly what you are asking...
Any 3-6 cell Mag will out-throw the Surefire 6P hands down. The beam isn't super smooth and you don't get that nice well-defined hotspot like you do with the 6P, but as far as actual 'throw', Mags are still very impressive.
If you want that smooth type beam and large hotstop and are generally happy with the actual brightness of the Mag, you can 'sputter' the stock reflector using $1 of clear acrylic spray paint and you'll likely be VERY happy with the result. The smooth Mag reflector maximizes throw without considering those ugly beam artifacts. The stippled type reflector of the Surefire does it's best to have the smoothest beam possible and it does a very good job, but there is a cost in terms of throw.
If you aren't so much of a do-it-yourselfer, there are aluminum stippled reflectors available... I think they are listed in the Group Buy section and offered by fivemega. If you want one, I'd try to get in fast as oftentimes his reflectors sell out very quickly.
Next issue is the actual brightness. The 6C is actually a pretty bright light Actually, I've never even held a 6C, but have used the 6D. But in a form factor as small as a 2D, you can use multiple NiMH AA cells and an adapter to get better brightness. Most of these mods require several other things though... aluminum reflector and glass lens that won't melt, a bi-pin adapter of some sort since the brighter bulbs often aren't PR-base like the stock Mags, and if you want to use the best and longest-running NiMH cells, you need to have an adapter(s) that allow to use the AAs in place of the D cells. You also are likely to need to have the inside diameter of the body of the light bored out to accept that highest capacity NiMH cells.
If you don't mind using the somewhat exotic LiON cells, you can also run different bulbs in a 2C Maglite with a stippled reflector. One of those is my next project.
It can be a lot of work, but sometimes the results are nothing short of outstandingly impressive. There is even a light called the USL that is so bright and so hot, that it will light paper on fire almost instantly! But keep in mind, there is usually a tradeoff between brightness and runtime and a lot of folks that use their lights often don't like only having 15-30 minutes of runtime on a set of cells.
There are other smaller lights that are very impressive. The 6P, first of all or the similar but cheaper G2. The Brinkmann Maxfire available at Target and Walmart for under $20. The Streamlight TL-3 which is my current favorite (and can be used with rechargeable 17500 LiON cells) and the recently reviewed Wolf Eyes light. You can read about all of these at
www.flashlightreviews.com