You could also look at The Oumier Wasp Nano RDA or Demon Killer's Tiny RDA.
Authentics of either one can be had for less than $20.00 and a Coilology SS316L Pre-coiled Performance Coiling Kits from hitthatjuice.com for under $15.00. The kit has 42 individual coils, 7 different types with 6 coils of each.
I normally use RTA's as my daily attys, but I keep one Geekvape tsunami rda built and ready-to-wick for new juice trials.
If you're dead-set on sub ohm/rba combo you could also consider the HorizonTech Duos Sub sub ohm tank. It uses HorizonTech Duos-specific sub ohm coils, Smok TFV8 sub ohm coils and also TFV8 RBA sections, TFV8 RBA and TFV8 RBA-16.
The RBA-16 utilizes a goon-style clamping deck.