I own a fair few mods(26 regulated mods) so can give you an insight into a fair few that you like the look of, the IPV5 as you mention is a very nice mod indeed.
It works well, TC is great on it, I own the SS version so haven't encountered any paint chips myself and can really recommend it if you like the look of it.
The RX200 as mentioned is another great mod-but the 510 pin is lacking and a weak area of the device, as with all Joyetech devices at the moment unfortunately. I haven't had a problem with mine though, I have in the past with the Cuboid but this was fixable.
The IPV5 does have a good board board by Yihi, my oldest dual 18650 mod uses a similar board, the Sigelei 150 (Original, I also have the TC though, and both are going strong after a lot of use).
In your price range the DNA200 is out of the question really, but you can still get a great mod in your price range. The IPV6X and SMOK Alien is a nice sized mod for a dual 18650 device-unfortunately these are 2 mods that I don't own at the moment though, so can't comment on them fairly.
I really do think this is a great mod though, the RX 2/3- if you are not sure if you want a single or dual 18650 device, you can choose, and in dual 18650 mode it is rather small-