The MM6 might work for you. The unit has Motif based sounds, some real-time control, decent screen, it is an arranger as well. More of a modern DJX really.
The internal recorder on the MM6 is an 8 track linear sequencer with no post song editing. It's more of a scratch pad... However, the MM6 ships with sequencing software, which will give you all the loop recording, and other functions of a sequencer that the MM6's internal recorder does not have. Plus you can get the instrument definition for the MM6 at the Motif forum for free, which opens up the entire sound set rather than being limited to the GM voices.
Also the Korg X50 isn't an arranger either. It is however MUCH more advanced in terms of synth abilities than the MM6. The MM6 is more of an out of the box "instant groove" type keyboard.
I'm sure the next suggestions you get here will be the either the PSR-3000 or PSR-1500, however they might be out of your price range, and you may be paying for features you won't really use either.
Squeak
[This message has been edited by squeak_D (edited 04-13-2007).]
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.