HaveBlue,
That thin wing is a balsa built up and sheeted wing AND it's two piece. That adds up to a marginal strength wing. You are not going to do 150mph+ with that wing. The Nemisis is an all carbon wing and is designed to pull 25G's, we know it is capable of 200mph+ and it can pull a pylon turn like no tomorrow. I've seen many F5B motor glider style planes (like the Supersonic) blow up in mid speed runs due to wings failing....and those were well built composite structures. You need to look at a more serious wing design if you want to go fast. I think you have a good idea in that style of airframe but a balsa wing in this size isn't going to cut it.
You can probably fit a 4-6oz tank in one of these fuselages and mounting the motor is no big deal, but depending on how fast you want to go will dictate what wing is on there. Another airframe that may be better suited is this:
http://www.nesail.com/detail.php?productID=1429
