If you sheet the wings and put in some carbon spars you can use some hot gas motors, that would get you going!!!
Seriously it looks like the motors are the slow part, I don't know for sure that they would fit but I would go with an inrunner like the Mega 16/15/2 here:
http://www.espritmodel.com/index.asp...OD&ProdID=3191
Shaft size is different so you'll need to mod the fan a little.
You'll have to use bigger controllers but it'll give you 4600 rpm per volt over 3500 for the e-flites, over 30% more speed. My recommendation would be buy the kit make your measurements and then buy motors, speed controllers and the biggest 3S LiPo's you can.
There are Hi Maxx'es that would work well too.
And then tell us how she flew....