Sounds like you are looking for the Remington 870 Marine Magnum.
870 MM on Gunbroker
Unfortunately, I don't know that they make the longer stainless barrels that would be better suited for hunting/clay games.
You living in Philly, I'm assuming the stainless is simply aesthetics, no? It is a sexy SG.
Personally, I'd suggest one of the less expensive, proven, blued pump guns that get all the rave reviews here on this forum. Start with a 26" or 28" barrel. This will both save you some money and allow you to shoot skeet/trap at some of the ranges that have regulations on barrel lengths in order to keep noise to a minimum. The range I shoot at is 26" min.
Starting with a Rem 870 Express Magnum should only set you back about $225 new. The left over $275 goes a long way in the ammo/rounds of skeet department.
If you were to pick up something like the Marine Magnum there is nothing to stop you from putting on a longer blued barrel in order to take advantage of the length. It might not look as pretty but it will make it a bit more versatile.
Hope that helps,
cs
Edit: BTW, is this really necessary
. Some of us have to drive minivans and Saturns:banghead:
Not to worry. My 99 Safari has a V8 with its name on it in the not so distant future. The Mrs. just don't know it yet.