Such a thing is not the job of a sequencer... stay with me... Well, I know what seppo means here but that's not strictly true either. A midi 'note' is just a number from 0-127. Whatever device receives it, can decide what it wants to do with this number. It could play a note in twelve tone like most synths, or a pecussion instrument or a sample or turn on an LED or flip a relay or move a robot's arm ;) As you've both mentioned, you can use pitchbend to fake the tuning you want, and it works to some extent, but with some synths you will hear this 'cheat', especially older boxes or when you have portamento turned on. Also, it's indeterminate - a certain amount of pitchbend may move the frequency to the desired one in your special tuning, or it may not, depending on the depth of pitchbend on the synth receiving it. It might move the filter cutoff, or alter the amplitude envelope, depending on the patch you play. For these reasons, the pitchbend method is mostly functional, but sometimes not. This is why you should use the tuning standard wherever possible, as it clearly defines the way that the receiver will react to incoming data. If that's not available to you, then as has already been said, you could write a custom midibox app, that will offset certain notes by using pitchbend data. You would want to have a table that stored the offset you want (your custom tuning) in cents, and store the pitchbend range (in cents +/-) of the receiving synth, then it would all be automatic, and you can use both hands to play :)