Righto, off my lazy bum now.
I've done a few concept sketches of what I want this thing to look like. I'll focus mainly on the beast and the baggage and if I have time I'll make a merchant to go with it.
The basic idea is that it is an air floating jellyfish/squid thing.
It has a gas sack that controls the altitude of it but it generally stays within a few metres of the ground so it can find prey, floating higher if predators are near by. I am thinking I will go for the beaked mouth rather than the toothy mouth or the mouth that is just a sphincter, although the last would make it seem quite different to anything else.
It will have multiple tentacles with a few longer ones used as probes and to ensnare creatures. the shorter ones also hold prey while the beast devours its prey (whole in the case of the sphincter or ripping it in the case of the teeth or beak)
The shorter tentacles also hold the beast in place in case of high winds etc as this creature mainly moves where the winds take it. In extreme cases it can use its longer tentacles to propel it along the ground for short times. It is at home as much over the water as over land.
It can reach great altitudes useful for when over oceans to avoid storms. (making this up as I go along)
It has been domesticated and used as a beast of burden for millennia. When well fed they are extremely docile.
Anyway, I'll add more to this info as I think of it.
If anyone played Morrowind (Elder Scrolls 3) you can probably see the inspiration from the Netch.
Here are some pictures
The first one is the beast, the second is hooks and things used for bringing it to the ground to access wares.