New to m*gs, want to make a hotwire

I want to build an ~2k+ Lm light with an AW soft start 3 level switch. Adjustable flood to throw would be a plus. I was thinking of using an inexpensive 12V 100W 2000 hr bulb and running it off of 4 32650 LiIons in a 4D and having it bored to fit 2x18650 to run 4S2P also (either way). I'm totally new to both m*gs and incan so I wanted to know what you folks think. Is it feasible? Would a 4D work? I'd have to shorten the spring - is there a replacement spring that would work better? Are there differences in hosts and what do I look for? This would be a user light and I will have spare batteries and a variety of other lights including a headlamp as well. Thanks. There is no voltage regulated switch available, right?

Thanks. The bulb I'm interested in is a 2550 Lm 100 watt. I don't really need it to be overdriven but I don't want to start out with 3 Li Ion at its minimum voltage, either. The Osram is a 10W.

Here's my bulb http://www.higuchiusa.com/products/medical/gy6-35/M-01142/

What are the best batteries to run my 100W bulb? I'd like multiple levels and $$ isn't tight, but not unlimited, either. I wouldn't be able to afford a premium FM setup I'd like at least 40 min on high as a target runtime. It wouldn't be all at once I guess if we find the right batteries and 'driver', the rest will be derived from that.

There are other switch substitutes in the works that could also work.