There are at least a couple of CT users over on the Navitron forum. You might find this topic especially interesting:
http://www.navitron.org.uk/forum/index.php/topic,19627.0.html

We have a perfectly good WC to septic tank, but inspired by that topic I've been doing a bit of experimenting over the last few months! I started with thewww.humanurehandbook.com approach (i.e. all in one). That was fine, but you go through prodigious quantities of sawdust and a full 25l bucket is quite a weight to handle - not the sort of thing you'd want to stumble with on the way to the compost heap. I've now moved on to a hybrid separate & cover approach, i.e. solids in bucket, with sawdust cover, liquid elsewhere (5l bottled water flagons are very handy...). That's okay but doesn't seem to be as effective at odour control, perhaps because you tend to use much less sawdust? So, the next stage is to move the experiment on to separation with forced ventilation/desication, as used by the couple mentioned in the Naviton topic.

PS. One "green" aspect of these systems I don't recall seeing mentioned is that if the loo is within the insulation envelope there's an associated reduction in heat loss, i.e. you aren't bringing in cold flush water which absorbs heat before being flushed away, along with a quantity of additional body heat material...

Of course if you're using the forced ventilation approach there'll be some loss of heat associated with that, but any cistern with an overflow probably has at least a bit of a draught too?