I have some square speakers that I purchased from All Electronics a couple of years ago that are less than 1/8" thick. They have a 1" round version in their latest catalog that is only .015" thick, item SK-218, priced at 2 for $1.
http://www.allelectronics.com
As David B wrote, Mouser Electronics is also a good source for speakers. The biggest problem is that unless you need more than one, the cost of postage is going to far exceed the cost of the speaker.
Also try:
http://www.tonystrains.com/products/tteexclusive_spkr.htm
Engineer Jeff NS Nut Visit my layout at: http://www.thebinks.com/trains/
http://www.mouser.com/search/refine.aspx?Ntt=speakers
Does anyone have a line on low profile 8 ohm speakers? I have some of the Soundtraxx 28X40 that are the right dimensions but too "thick" at nearly .5 in. Is there anything anyone knows of in about this size range (think 1" x 1 and 3/4") that are lower?
Generally, who but Soundtraxx supplies good speakers?
Thanks.