The Seal Pup is a pretty good knife for what you want.
They may not LOOK like the Seal Pup but alternatives I would look at, and among my favorites for the purpose, are:
-CRKT Ultima - maybe the best handle for such a knife I know of. Sheath is a little bulky.
-Ontario Ranger Kerambit EOD - Arguably the best basic, no frills kerambit out there.
-TOPS/Buck CSAR-T - Mighty fine, tough knife; I have the little brother to it (CSAR-T liason) and love it.
-Browning Backlash - for something that LOOKS the part; stainless steel pommel and hand guard.
-Gerber Guardian - Old standby. American made. Tanto. And a TacHide handle that is great for grip.
-Puma SGB Boot Knife - a recent find for me. Might be my next booter. Nice lines and efficient build. Good looking.
-BokerPlus Mosier - as a nice wild card to throw in. Probably the least known. Very basic but looks good to me.
-HK Conspiracy - First, it's a Benchmade. Second, it's a tanto. 58-60 Rockwell. Minimal sheath. Great G-10 'gatorskin' grips. Probably the most down-to-business.
If none of these are to your liking there are a lot more out there.