No reason I can think of not to use rump steak if you have some to hand; the only thing to remember is that beef tends to soften, then firm, then soften again when cooked, so you are either going to have to cook it fairly quickly or leave it to stew, nothing in-between. As for spices, turmeric, cumin, coriander and perhaps fenugreek,would be my choice for a mild curry. I have never cooked a curry without any chillies, so I can't vouch from personal experience as to how it might work out ...
** Phil.