I think that a Spyderco Mule would meet your requirements.
The Spyderco Mule has been released in about 30 different steel types to date. See:
Spyderco Mule Team Project. Cost and availability (for the blade alone) vary greatly from around $100-$400 with a current median price of around $175-200.
All of the blades are flat ground and very slicey. The blade length is exactly 3.5", OAL 7 5/8" and blade thickness 1/8".
Spyderco sells black G10 scales (others are available from Halpern Titanium) and a black Bolatron sheath for it, which have been out of stock for awhile but are both available right now. See:
Spyderco Mule Team Accessories
Spyderco Mules are often sold as a package w/scales and sheath on the 2ndary market. One such package for a CTS-XHP Mule is still available on the Exchange for $275
here but another package recently sold for just $150
here.
I know that the 2nd Mule package w/a ZWear blade sold for $150 because I was thinking about buying it. The combined cost of the scales and sheath alone was about $100 and the net cost of the blade would have been "only" $50 which was about the original release price, which made it a GREAT deal!
So, it pays to keep looking and to be patient if you're looking for a "deal" on a Mule package. The price for the current Mule package still for sale is not unreasonable but at that price you could put your own package together.