Stealer hybrids come in various varieties, depending on how close they are to being full-on purestrain genestealers. I thought that the flagellant bodies would work well for the second generation hybrids - also known as acolytes - who are well down the bestial end of the gene pool. I imagine that they would cover their strange bodies with loose robes to hide the awfulness below, and would probably be regarded as holy by the cult anyway.
I had some of the truly dreadful Space Hulk hybrid bodies from the late 1980s, which may be some of the worst models GW has ever produced (the Space Hulk marines were pretty dreadful, too). I took the arms off them - the arms are ok, actually - and put them on the flagellant bodies, along with some spare hybrid heads. I bulked up the shoulders with green stuff to suggest size and to make the arms fit better.
Some weapons and pistols were added, and in a couple of cases I kept the odd flagellant head or arm to suggest slightly less inhuman members of the cult. Then came the painting.
It's a fairly simple paint-job and certainly not my best, but I think it works fine for the unit. I enjoy doing their weird skin tones.
The second batch has an extra guy, armed with a massive circular saw (on the left below). This chap was made from the top half of a Warlord Games model from the Gates of Antares range: a "Ghar outcast". The legs came from an ancient plastic Grave Guard model from Warhammer Fantasy Battle. I sculpted him a clawed arm out of green stuff to make him fit in more.
A little crude, perhaps, but they work well as a unit. I should be able to get a few more out of the set that I bought. By my standards, this is bulk painting, and I can't say I enjoy it as much as the usual style.