Okay, here's a little update...
I was recommended quite a few ones by different people...
First the T-REX Spin Doctor (http://www.youtube.com/watch?v=wIbarTPNJkg
), which I think is really fantastic! Did anybody ever try it or even used it for some time? I love the motorised knobs, and it seems like it's being able to cover a lot of sounds. And a very BIG bonus are the 4 different channels.
A friend of mine also recommended the Blackstar HT-Dual (http://www.youtube.com/watch?v=J9j8Gd6TBVw
). It's a bit cheaper than the other one, but also less versatile. And I think the tone is not as warm as the T-REX.
Last but not least I was told to look at the Carl Martin Plexitone. (http://www.youtube.com/watch?v=Ng4peS3MjrY