Ive had some passing familarity with C4..but I suspect its not
particuarlly applicable to your situation.....though it does tend to
place a new outlook on sh.t disposal.....

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont  kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the sh.t out of you
for torturing the cat."  Gunner

You would be better off with a free-standing Porta Potti such as the 585.

http://www.thetford.com/portable_pp585.cfm

It is my understanding that the cassette potty was developed specifically for
installation in an RV so that the holding tank can be removed/replaced THROUGH
the side wall of the RV.  I suspect there would be nothing to be gained by
installing a cassette unit in a cabin.

As for odor and ease of disposal:  No problem.  We used a top-of-the-line
Thetford Porta Potti<tm> in our camper for 13 years.  It worked like a charm,
was easy to service and never gave us a problem.

Good luck!

I have experience with boilet NE compost toilet and RV toilets. I
discovered compost toilets suck in an RV, because you still accumulate
and must dispose of urine. Without some way to evaporate the liquid
there's no advantage over a conventional RV toilet.

cassette  toilet:
http://www.lewisgray.com/Sanitation_products/Cassette_Toilets/howitworks
.htm

The problem with any self-contained toilet is that holds rotting sewage
inside your living space, so even a tiny leak can put a considerable
stench inside your cabin.

I suppose an "island cabin" is a cabin on an island?  That toilet is
designed for RVs without holding tanks. You'd have to cut a considerable
hole in the side of your house. The walls of a house are usually much
thicker than that of RVs. Obviously this toilet don't have much
capacity, maybe 5 uses? It was designed for RVs, imho that's where it
belongs.

If your "island cabin" doesn't move, I suggest using a homemade sawdust
toilet with your outhouse. This is similar to what was commonly used
with outhouses in the previous century. However i'd modify the sawdust
toilet so that the bucket sets inside a pan or a bigger bucket, so one
day when the bucket begins to leak (like all buckets eventually do)
you'll notice the leak before it puts a permanent stench into your
woodwork.

Make a sawdust toilet:
http://www.jenkinspublishing.com/sawdustoilet.html

I'll post it here, you can go email yourself  <G>

I have a 135, I had it in my pop-up and used it. It worked. When I sold the
pop-up I kept it and used it in the garage. (Unheated nad pretty much
uninsulated).

No, odor even in summer. I used the formaldahide formula though.

It was only ever urinated in in the garage, so I can't speak about fecal
odor in excessive heat.

Ed

I use a sawdust toilet with no problems and no need to separate liquids
from solids. Inexpensive and easy. Free info here:
http://weblife.org/humanure/default.html

~kris