SPX hedging?

SPX is based on S&P 500 Index cash value:

http://www.cboe.com/Products/indexopts/spx_spec.aspx

SPY "approximates 1/10 the value of the underlying S&P 500 Index"

http://www.cboe.com/products/indexopts/spy_spec.aspx

Are there some other index based exchange instruments available (closely following cash value)?

Or is SPX options to be hedged with ES/SP futures? Are SPAN rules applicable?

Thanks

 

There is NO cross margin between futures and equity based products.