Onguard U-locks are heavy SOBs, I have one as well as a couple of Krypto U locks and the Onguard doesn't get to go on bike rides anymore, it just guards bikes when they're parked on my deck.

Go to a couple of shops and compare brands, you can easily make up a U lock - cable combo without buying one prepackaged. Seat security cables are available, and locking wheel skewers too.