Also, is the Shiver SC a good fork
No. Of all the Zochs the SC Shiver is the only one that I would not recomend. You would be much better off with a DJ 1 or 2 for the type of riding you want to do. I say this from personal experience and from other riders I ride with.
A good ht can handle drops up to 10' if you know what you are doing and is alot easier to ride trials with then a fs. If you do get a ht I would suggest either a (in your price range)Cove, Brodie, Kona or any company that build ht's for Shore type of riding.
As for FS rigs, take a look at the IronHorse SGS and the Brodie
8-Ball. You also may be able to find an '02 Stinky for $1000 or so.
As for SS rigs, I ride one for my urban, dj and trials. That way I never have a problem with the chain jumping. As for SS rigs check out the DaBomb "Mindbomb". It is a sturdy frame and has the horazontal dropouts so you do not need a tensioner. Also check out Surley. They also make a good frame.