I wanted some of the major elements of Protracker/FastTracker behaviour available to me in modern DAWs, but without the fastidious attention to detail that frankly inhibited my creative process for years when I used to argue on forums about the minutiae of interpolation techniques, etc. I've coded my own MOD/XM replayers, I know what's involved in getting *the sound*, but I realised that life's too short and that what's just about good enough for my ears is more than good enough for casual listeners. It's great that people are still concerned about the details, but this is a very personal thing based on the sad fact that time is money and I need to actually finish tracks to deadlines rather than indulge in fiddling with bytes 
SO... I made Chipslapper, a Reaktor ensemble. Yes, it requires a licenced (or pirated) copy of Reaktor, but I haven't the skillset required to make a C++/JUCE VST so it's the next best thing in terms of portability between Windows, OS X, Renoise, Ableton Live, Logic etc. You can see the details on the page there, but basically it does:
- all the waveforms joule listed plus freehand waveform drawing
- LFO'd PWM
- ADSR (but not freehand-drawn envelope)
- vibrato with a sweep (just like FT2)
- a nice big pitchbend value so you can draw pitch envelopes with DAW automation
- a choice of mono or poly and a basic delay that's designed to sound like multichannel pattern-delay
- a waveform slot for files imported via Reaktor's Sample Map system
- some control over sample start/loop points
- an extra waveform type which is basically all of the samples from ST-01 
- a random panner with variable maximum width
It DOESN'T have an arpeggiator (I intended to use built-in DAW MIDI arps), pan envelopes (easily automated in the DAW, which felt like a better solution to me anyway) or randomised step modulation - but read on for more about that last one...
Stuff I wasn't bothered about included compression, filtering, or anything else that I'd probably be doing as part of my general mixdown. Again, fidelity (relative or otherwise) and historical accuracy weren't critical, but 'feel' was.
Then a few nights ago, I decided to redo the whole thing in Max/MSP, to use with MaxForLive in Ableton Live. Then I decided "fuck that" and remade the whole thing just using native Ableton Live devices instead - loads of Sampler instances filled with waveforms. It's called Chipslapper Rack and you can find it on the page linked above. And, although it's arguably more limited than Chipslapper in that it's only for use in Ableton Live, it's got a number of advantages (mostly outlined on my page). Pertinent to this conversation, though, are things like:
- it uses looped 64byte waveforms that I created myself (32bytes wouldn't loop in Sampler) rather than Reaktor oscillators
- Interpolation can be disabled or set to one of three quality levels in Sampler, so they're mostly off but you could change that if you wanted
- Step modulation for pulse waveforms is implemented and it's randomised With only changes on note retrig, as joule specified.
- I've built an Ableton Arpeggiator into the rack this time, preset to a close approximation of the kind of arps I often use - but configurable via Macros
- As well as a delay, which works a little better than in the Reaktor version, I've also included Redux for sample/bit reduction. Probably unnecessary, but once in a blue moon I'd use it for a cheesy automated drop/fadeout
- Input velocity can be adjusted on the panel Macros too, as well as the ADSR, the random pan width (0 == centre), portamento time (you can dig into the Sampler instances if you want to change between portamento and glide; sadly that option couldn't be Macroised)
- White, pink and brown noise, still beholden to the ADSR and most of the other features
- Best (worst) of all...I've now got the first three ST-XX sampledisks built in as the final three Waveform types; 'ST-XX Sample', needless to say, lets you scan through all of them. A few are missing from ST-03, as it's got more than 128, but who cares
Again, the big caveat - I wrote this for my own use. It does exactly what I need and it makes it really easy for me to get some of the sounds/behaviours I want in a fully-sequenced multichannel DAW track without having to render out of Milkytracker or whatever, as well as taking advantage of all the handy parameter recall stuff in Reaktor/Live. If anyone else finds either of them useful, that's great - I've put them both up for free, so go mad. I should say that I'm unlikely to implement any major changes or alter anything that somebody might think isn't 'authentic' enough, but since Chipslapper is an .ens and an .alp, the source is all there for people to mess with if they want.
Hope it helps!