I trade for VTrader and we offer risk based haircuts. There are other places that do as well. However, the options side of the business is very different from the equity side or futures side. Most options firms want you to come in with 50k to 100k. No one is going to let you trade overnight options for 10k or 25k. Not even Simplex. My best advice for you to is trade options on futures where you will get Span Margin which is very simliar to risk based haircuts.