Kirk,
You're not going to get a genuinely good variable focus for that price as far as I know... they tend to lose a lot of lumens and good ones that are well built are rare and fairly expensive. The only thing I can think of right now is that Wolf Eyes makes a vari-focus light, but I don't remember what it's called.
I'd recommend you go with something that has been designed as a dedicated gun light that will be a strong thrower. The new 4Sevens Maelstroms are such lights; they're specifically designed to be able to deal with recoil and not blink out from the inertia of the battery compressing the rear spring and breaking the circuit for a moment, causing the light to go out. I think the current one they have that's specifically designed to be a weapon light is the X7, but it's in the $150 US neighborhood.
If you want something cheaper, check out Jetbeam; they'll still be more than your target price, but less expensive than the X7. They have a nice selection of accessories and most can take a tape switch on a cord for your trigger, so they'll come on when you lightly pull on the trigger.
ArmyTek is a new company, but their lights are supposed to be very throwy and well made, good for weapon lights. They're pricey too though.
Hope this helps.