Also I'm wondering if you are planning to use the LEDs for close up flood, why don't you try what McGizmo has done here:
http://www.dmcleish.com/CPF/L1-Diamond/index.html
Just having 4 on each side would give you a very good candle stand light.
Having 3x5 watts on the from in the very first design can give pretty good flood with mcflood reflectors. And a P90 in the middle gives you your 100+ lumens.
IMHO, the batteries should all be used at once and not drawn bank by bank. By sharing the load among all batteries, you get more life out of them. You can have the uFlex driver for both the 5 watts and the 1 watts, and a LVR for the P90. Using 9 123s in series gives you a very high voltage (27v) to step down from which can give the P90 a very long run time. At the same time, the uFlex driver (if I didn't remember wrongly it's a step down circuit?) can also distribute power easily to the LEDs. Less current draw on 123s at any one time = extended battery life.
In the above mentioned configuration, the Candle Mode and the Mcflood 5 watt mode, and the P90 mode, all give you very good flood options from 360 degrees flood to directional flood, to longer range flood. Should be what you are looking for. Except that machining will be a nightmare. /ubbthreads/images/graemlins/smile.gif
Oh, regarding switching, you can have a single on off switch, and a 3 mode selector switch. If I'm not wrong, that should make choosing which mode to use a lot easier.
*edit*
I'm wondering if the 3x5 watt configuration, driven at spec, would outpower the P90 and render it redundant even tho Mcflood is used? It sure is expensive using a total of 15 watts for flood when a CCFL tube might have been a better bet...