I just saw this again and sky's answer so I will put in my two cents.
In terms of writing. I have had this year quite a few stories published over The Deepening, and many of them are on "Jewish" topics though their audience is far far from Jewish. "A Pot Of Gold", "The Heretic", "Kapparot", and one coming out in January "Elijah's Coins" are certainly on God-man relationship themes and there are others but that is enough of a listing.
I do not think you will have any prejiduced against a mainstream story that tells something from a Jewish perspective. Albeit short stories are incredibly difficult to sell to begin with.
Short story markets are incredibly difficult and I am always on the lookout for real and established ones. Certainly, Bellow, Singer, Weisel etc. just to name a few did break into this market.
As to a Novel which is "jewish". There are some fairly famous Jewish writers with themes in all genres. The Decker series is one mystery series which is really successful by Kellerman and is based not only Jewish but Orthodox Jewish, even ultra right orthodox Jewish. Bellow was a literary fiction artist. Potok. Singer (nobel prize for lit with Weisel). Oh there are hundreds these days. Naomi Reagan. and do not forget The Red Tent.
It is a matter of finding the "right agent" here I think, more than the right publishing house, as all the majors are open to it. (The non-fiction world is a bit different)
This year was my year for short stories and progressing in WIP's. But to be honest, I do not think writing about Jewish themes is a minus. I just think you have to be real good.
I have no clue what mag. Sky runs or if it is widely read, but you could try his mag and others as well. It is not that there is a lack of markets. Just too many bad ms. flooding the piles.