Does anybody use pattern gobos with AB?
Any manufactures? Holders?

No focusing spot.

I have just experimented with this issue.

Using a non-fresnel (unfocused) light source, you can still get sharp, well-defined shadows, but the gobo-type device has to be close to the subject. The farther away from the subject, and closer to the light, the less detail.  It would cost a lot of money to get a gobo big enough to be close to the model--it would have to be as big as a window.  Which is what you are imitating.  You could buy a cheap set of venetian blinds or buy a large piece of foamcore or paper and cut out your pattern.  Hang that near the model, out of frame, shoot your light through that (a grid in the reflector helps tremendously), and there ya go.

edit: hard to tell in the closeup, but I used this setup with my avatar.

2 cheap ways to do it.

1--slide projector-- or filmstrip projector. (eBay)

2--Ikea sells a gobo spot with a few cookies and with a little ingenuity you can make others, $49.95 and can't go wrong. 

http://www.ikea.com/us/en/catalog/products/10050674

No, not if you creatively set up the lighting specifically so you are not aiming a bare strobe at the effect you are creating. Usually this is used to light behind the model, and then use diffused and or spots on the model that don't wash out behind.

Something like the old "Turbo F-16" spotlight attachment or SP Systems' spotlight attachment are likely to be as cheap as they get. You could build your own from a pair of fresnel lenses and a sliding tube or box, but the cost is likely to end up more than one that's already built.

Those units will not give a knife-edge crispness to the image, and are likely to have some color fringing, but to add texture to a background, they're great.

If you really need a crisp projected image, and need it strobe-based, a dedicated unit is likely to be needed, and they're not particularly cheap; used they'll start at around $500 for the lower-end models. Most of the larger strobe makers (Balcar, Broncolor, Dyna-Lite, Elinchrom, Profoto, Photogenic, Speedotron) make focusing spotlights. Norman's older Tri-Lite is another option, if you can find it used.

If you're particularly handy, you could gut an existing theatrical spotlight, and put a strobe head inside. It'd be tricky to get the alignment of the bulb right for the best results, but it's been done--it's how Speedotron's old integrated spotlight was made; they converted an Altman projector.

You can get:

http://www.dennymfg.com/store/index.php … &Itemid=26

attach it w/ one of these:

http://www.dennymfg.com/store/index.php … &Itemid=26

& you're set...

Paul