If you're willing to bite the bullet and skip the 18650, go to two-battery mods:
notcigs Infinity Pro is a solid, durable, tube VV, at $120 including two sets of batteries and charger (though you could skip the charger if you have one), code "ECF Buzzkill".
notcigs VVPV box top-feeder is out, metal body. Paired with an IO6 atty it's a very nice setup (I use Wharfrat's IO6 sleeve with it, to allow use of a normal drip tip, punch the sleeve to take the feed tube).
Reos VV Woodvil is due out very soon, sounds like a week, two at most, same excellent electronics as the notcigs Pro series, wooden box bottom feeder.