Ok, here is my mock-up for a for a light engine. (in inches unless marked)

I'm shooting for a vertical something like Punishers box. But for now I'm working on the light-engine.

Design constrains:
Standard Lens, may update later.
Standard LL Bulb and ballast.
No rebuilding when upgrading lens kit's later. 17" light cone at 220mm.
No really hot parts where fingers can get to them without a screwdriver.. Kids in house.
No combustible materials in direct line of sight to bulb.
Fine adjustments available without direct line of sight to bulb.
- Center bulb's arch chamber (tilt, slide in/out)
- Adjust reflector's position (x,y, height) (x,y not shown at this time)
Grounded, Grounded, Grounded.
No direct cooling of bulb.
Mountable on an angle.
Keep glass in box if bulb shatters.

Known compromises:
Size & weight.
Light Lost in the glass and Lexan.
Complexity of scissor-lift adjustments on reflector.

Notes:
May add nomex (fiberglass like sheet) between the mogul and the adjustment plate.
Temp sensor on inner box to run fans. (not shown)

complex reflector adjustment isnt really needed. once it is spaced you only need to move it side to side (along the plain of the collector fresnel). but the scissor idea is pretty cool, you could make a bigger one to support the whole lamp house to adjust lamp to frensnel distance.
both glass and lexan are not needed either. having both reduces output. with just glass you need a UV filter but with lexan you need it further away since it will melt.
you also wont need nomex since if you make the box out of aluminum with forced air cooling it wont get that hot unless you paint the inside black. with my lamp house the outside reaches 150 degrees max but usually i can touch the outside. if i turn off the fans it reaches 200 so if you paint it black it will really get hot.

Unfortunately, yes I'll have some light loss with the lexan and glass but I want to keep the cooling circuit of the light engine seperate from the cooling system of the rest of the box.

I was hoping with the double metal box construction and the forced ventalation the between the boxes would keep the lexan far below it's melting point. Still it is close the bulb. Guess I'll have to find out the hardway.

One layer of heat shield should be adequate. (BTW, I like your monniker.)

The general layout of the light box looks good though.

I agree. I would go with an adjustment on the reflector similar to the bulb. stick it on some screws so you can space it then allow for slight adjustment in the horizontal plane. in the vertical plane you shouldn't need more than a few mm adjustability.