Would this evenly expose 17x22 ?
From a couple of inches distance, I think so, yes, assuming you go for the 15x22 option he mentioned.
Keep in mind as you increase the distance between the light source and the printing frame, you gain some exposure area/size. With LEDs it's less than with tubes and especially metal halide bulbs since the light of LEDs tends to be a little more directional, although most come with a fairly wide angle 105 degree lens fitted onto the die.
As to the metal halide bulb in the machine you might get from your workplace: it's a 400W unit which will do OK for your purpose, but it won't fit in the drawer idea. You'll have to place it at something like 3ft minimum from the printing frame, which is also necessary to keep the print from heating up during longer exposures when printing with processes that are sensitive to this (carbon, gum probably too). The advantage is that a metal halide bulb is a point source, although the practical relevance of this advantage depends a lot on what and how you print - in most alt. process printing it's not reall necessary.
Personally I find metal halide bulbs a little awkward; they take time to heat up, they emit a truckload of heat and light you don't need, their light output tends to reduce as they age (which is more pronounced and happens quicker than with LEDs) and there's the whole distance thing...in your place, I frankly wouldn't recommend that direction. On the other hand, some printers really swear by their metal halide setups - but these are nearly invariably people who have been printing for decades and who are really intimately familiar with and attached to their trusted equipment.
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