They really aren't very difficult. I printed out the plans and gave them to my other half as a project for my home-schooled son. It's no thing of beauty, but it's sturdy enough to hold even my somewhat considerable weight, and a bit of sandpaper and a coat of varnish hides most bits of rough workmanship. The worst sides can always be positioned against the wall
I'll second Burra's post, a "loveable loo" really isn't too hard to build.
It's basically just box with a hinged lid, a standard toilet seat attached to the lid, and a 5 gallon bucket inside the box. You may be able to have the wood cut to size at the store, and just assemble it at home.
You can also buy a snap-on toilet seat from an emergency supply store. These are a bit smallish, but do work.
You might be able to find someone to build one for you, too.
One more thing - we couldn't get hold of buckets in the same size that the lovable loo was designed to take, so we bought up several of the closest we could find, all the same size, and made sure the hole was the right size and the base was adapeted to hold the bucket up high enough. We could have made the whole thing shorter, but I like my loos high enough to get off easily!
If all else fails, try camping stores. We have a thing called a "luggable loo" we got at Canadian Tire. which is a 5 gal. bucket with a toilet seat made for it. The seat seems to work on any other 5 gal. bucket we have around. I doesn't look as nice as the wood cabinet.... and is therefore not loveable... but a box with a hole to fit the outside of the bucket below the seat could make it look nicer. Even a cardboard box with a few coats of left over paint on the outside would work.
Diego Footer on Permaculture Based Homesteads - from the Eat Your Dirt Summit