Some swords made out of stainless are quite useable... but expect it to be from a custom smith (Barry Dawson for example) running anywhere from 2000 to 5000 dollars (more or less).
A SFI thread:
Stainless steel - heat-treatable for flex?
Another SFI thread:
Why Stainless Steel is not [necessarily] Crap
For something very tough and semi-traditional (furniture, fittings, construction, etc.) try the ATrim-ASA collaboration:
www.atrimasa.com - they also sell Western/European style swords by Gus Trim.
www.chenessinc.com - the very low end - the 9260 blade seems to be a good bet (thru-hardened, there is a new differentially hardened one) - don't expect geometry to be all that great, and the handle construction is suspect (pre-made and hammered on, last I heard - may have changed). GOod customer service. CHECK the handle to see if the core is cracked.
www.oniforge.com - some good stuff, a new company with some pretty good swords and apparently good customer service.
www.j-armory.com - see Furuyama and their own J-Armory line. Both are good stuff, and have direct design input from Bujinkan and other foreign JSA teachers.
www.coldsteel.com - usually a bit overpriced, solid cutters. Handle construction is also iffy - check. QC tends to be okay, depending on retailer.
May I suggest you browse the rest of SFI and feel free to search as much as you wish. I don't think registration is required except to post....