Update for everyone. Thanks very much for the ideas. This is a little side project for me, I will be hanging around, but I do have a day job (for which I write Java code, busman's holiday anyone
) so I won't be turning around addons at speed.
I think I will be creating a new addon, because I really don't want to steal zipp's work. However, it will contain "tier 2" and "tier 3" machines. Partly I'll do this because all I have of Zipp's code is decompiled, so it's not the prettiest stuff. I have a couple of ways I want to make things better so it's probably easier to start from scratch, metaphorically.
Give me a week or so.
By the way, looking for names, I noticed that what we've called Macerators in IC2 are probably more properly called crushers or mills (http://en.wikipedia.org/wiki/Ball_mill). Macerators are actually things that chew, like your mouth 
So here's what I think:
We have tier 1:
Elec furnace; Macerator; Compressor; Extractor; Recycler
Tier 2 is going to be (my additions in red):
Ind. furnace; ball mill (upgraded macerator); power compressor (upgraded compressor); hydraulic extractor; dust recycler
Tier 3 will be:
Blast furnace; rotary ball mill; power compactor (t3 compressor); vacuum extractor; magnetic recycler
Tier 2 items will be slightly less powerful than the Adv Machine versions (except furnace of course); they will spin up and for extractor; compressor and ball mill will generate small amounts of "dust" randomly as a side effect for feeding into the dust recycler (for more predictable scrap). (Expect 1 dust from a stack of ore or something similar, not meant to really replace anything current, just a little "benefit").
Tier 3 will be able to process many items simultaneously (blast furnace up to say, six; similar for the others) as well as more reliable "dust" generation for the recycler. The recycler "magnetically" separates the dust so there's a small chance for "small pile of iron dust" from dust gathering, is my thought (as well as usual scrap).
Dust mechanisms will be as outlined above: adv recyclers "collect" accumulated dust from machines nearby for processing, but only when powered. T2 machines will not be as good for range or maximal accumulation as T3, obviously. An interesting side effect of this mechanism is the idea of "clogging". If a machine becomes "full" of dust, it no longer works very well. Probably a real problem for efficient T3 set ups 
Tier 3 spinup will be slow, and you won't be able to turn them off and on on demand though- once you turn them off they remain "hot" for some period (maybe an MC day) and can't be reactivated without exploding. Also, they process nothing until they hit power, and will probably draw 5-10 eu/t to remain idle.
What do you think?