The only way to pitch shift a VST instrument in Renoise is using the panning column effect 91 xxyy. It sports a few problems, the first one is that it doesn’t get back to the middle of the pitch wheel soon enough, and the next note (if there’s no note off/cut between them) will not be in the regular pitch even when typing 91 4000 (reset pitch controller), it’s a bit clumsy doing pitch bends that way, the only other way is recording the pitch wheel from a midi controller.
First idea, maybe there could be some sort of meta device which will allow you to draw those pitch shifts yourself? (like, for example, in Cubase SX) but maybe even better than that would be-
I tried most DAWs and sequencers out there but yesterday I had a true surprise:
a friend of mine who uses Fruity Loops (FL studio) showed me that he can choose two notes, no matter which note- easy as… just select the “slide” note and you get perfect pitch slide. Between c0 to e10… any length you want. 
then he takes this file to SX to mess with audio options that unavailable in FL… now that’s freedom. 
How on earth do they do it and what do you think about having that feature in Renoise?
No buyers I guess? Think about it… the possibilities! 
I’m sold. Well, the Fruityloops thing you described allows a bit more freedom, it seems, but standard PT/FT/etc tracker toneporta has even more freedom, in terms of letting you adjust the speed of the slide row by row! If the pitchwheel control going into the VST could be abstracted somehow, and controlled by the same toneporta command as Renoise uses on sample instruments, that would be excellent. It’d bend the note as the wheel would (in relation to the modwheel settings within the VST) and then ‘snap’ back to zero for the next note action. If the abstraction took into account all of the actual MIDI commands necessary to make this a transparent process, then the MIDI line would still be compatible and not Renoise-specific.
I want to say “this would be EXCELLENT” but what I’m really thinking is that this would simply be bringing MIDI control into line with trackers’ traditional, and better, way of handling pitch slides after all these years:D
actually the only reason for which I didn’t reply is that we already written a lot about this topic. I of course agree that a new solution should be implemented, but lots of things has to change during 2.x cycle, so let’s see…
how to say… this is not the best moment for suggestions like this…
It should simply be able to be added to automation, and Enhancing the Automation Resolution, No snap on lines or ticks or whatever. That would be enough. =)