I have always thought the heavy weight (48 lb., glossy) paper stock used for brochures and flyers, or the bulk roll stock used for magazines was what you are describing.  The 8-1/2 by 11 inch brochure/flyer paper is available at just about any office supply store, or even the printing shop where you will get your playbills printed.  The roll stock is from wholesale outlets supplying the magazine print industry, but since it comes in rolls 4 feet, or 8 feet wide, and hundreds of feet long, it is impractical for the local printing service to use it.  Just to keep it simple and less expensive, I would suggest you consult with your printer.  I'm sure they have (or can recommend) the paper stock you're looking for.

Edited by Spectrum - 5/29/11 at 5:33pm

Thanks for the replies.
The thing is though, I am the printer. I've printed before (Portfolios for grad school), but I've been reading on line that the paper I've used in the past, HP semi/glossy, has gone down hill quality-wise.

My fear was ordering a whole bunch of paper and having it mute all my colors and that sort of thing.

I'll probably end up going to a couple print shops around here and testing some papers. If anyone else has any experience, feel free to give some advice.