edit: I just noticed this was on Vinh's Subforum, if you want something from him, I highly recommend like Agin said trying out some of his dropins- you can even get them potted. They make next-level duty lights with VN4. I have a G25C2vn with a W2 and SBT90, both would be stellar WMLs and VN4 still works with the Eagtac remote switch.
Vinh as a matter of fact has a Scout light up right now with a pretty great price and will be top notch performance, I would 100% go for that (no really, I would if I didn't just buy two other WMLs.....)
Cheap as possible but still reliable- Streamlight Protac HL-X
$200 ish- right now there are Surefire scout lights on sale for about this price and I would 100% pick this easily over the Streamlight
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$300 ish- Again Surefire scout, or Arisaka Defense 2 cell body with a Malkoff E2XT head.
Other options- grab any standard 1" universal light mount, a Surefire 6p or Malkoff MD2, and a M61/ M61T dropin can be assembled for around $150 and be a bomb-proof super reliable setup with options to add and change parts further down the road.
My AR15 uses a Surefire M962 w/ MDM4 and M91T currently, going to try a Scout DFT as a smaller setup.
My 870 uses a Surefire 618LMG Foreend and M61N dropin.
Sig P226 has a SF x300u-A, Glock 21 with Streamlight TLR-1HS