Interest-rate futures bid/ask spreads are VERY tight for options at or very near the money. I am speaking of major markets like Eurex Bunds, CME Eurodollars, and CBOT Bonds and Notes. Floor brokers will generally get very good fills on smaller orders in the interest- rates. I usually "give up the edge" to floor brokers on smaller retail-type orders (1 to 5 lots) as an accommodation. Rand Financial's 2,000 lot order for at-the-money calls is a slightly different matter, but they will be able to do all they want as long as the futures are there.
NYMEX Oil and Nat Gas is good, Agricultural bid/asks are fair, and stock index options market-makers generally want a big running start.
Remember, if the commodity's underlying attracts commercials (banks, dealers, food processors, refiners), you will get tight markets because they are generally there making markets themselves.
From my experience, stock index futures attract more speculators, arbitrageurs, and hedge funds than pure 'commercials' from the literal sense of the word.