I'm a big Peter Green fan and I'm getting great results with a Rivera Chubster 55 - it has two channels, one voiced like a classic Fender and the other will sound like a Marshall or Hiwatt, classically British. It's like getting two amps for your money and the range of tones due to the sensitivity of the pots is amazing. I also tried a Mesa Boogie Express 5:25 today and it gave me the raging horn - very expressive slightly compressed sounding clean tone which accompanied a Les Paul very well.
Please remember that in Peter Green's day they'd use any decent valve amp that was available and get a similar tone. The sound is contained in the feeling that is in the gut, which transmits to the fingers and is expressed in a big way by the pickups you are using. I would highly recommend alnico II magnets in whatever pickups you are using - any good traditional PAF wil get you in the ballpark but the BKP PG set are particularly good.
And practice yer vibrato !