I think an el34 based amplifier would work great with your speakers. Prima Luna, Triode Corporation, Yaqin... all great push pull designs that would give you some control. I'm not sure I'd go with a Jolida or Rogue with those speakers given the tonal balance, though others may disagree. Like mentioned above about 15 watts - I'm not sure it would be enough. I'd consider 30 to be more in line with minimum power.
If you like the single-ended sound and need more power, MastersounD is about to ship me the first batch of the BoX, a 35 WPC parallel SE integrated that will retail at $3,000. I could see it being a good pairing and likely enough power to control the Focals. I am the distributor so take that as you may.