Something for you to consider are Butterfly bars. I rekon they will be just what you're after. Starting from the clamp they go forward, theres a forward parallel grip position, they curve back giving you a perpendicular position and then curve back to a parallel closer position which is where you bold on your standard moutain bike controls. You can play around with lengthand height of stem or angle of the bars to get just the positions you want.

Do a search for butterfly handlebars and you will see what I mean.

Regards, AnthonyG