Sheep, i think you should look around in the jet section of this forum some. Turbines are very very complex, and doubling the amount of engines gets you struggling with technology rather quickly. The'res just so much attached to get a reliable system.
That is also the main reason why most jets you see are single engine, and sometimes use bifurcated tailpipes (see F-15 e.g.).
Also have a look at the price. If you will be building 2,5 meters in Length you will be talking 2 x 120 type turbines, each one setting you back about $3000 plus. Figure another $1000 for Radio gear. And add another $1000 for a custom gear (e.G. HaWe or WaBo). Add it all up, add an airframe around.....

Read around in the jet section, and maybe visit a jet meet to see what is really involved with operation of these things, they are absolutely uncomparable to a glow engine.

And as to construction: check out http://www.su27.de/
that is the homeopage of Harald Huf. He explains step by step (with a lot of pictures) how he worked out the project from scratch....that will give you a pretty good impression of the work involved.
Because of the high stress put on turbine airframes, most designs will require a composite fuselage, so don't expect to be able to build it of wood.

I hope i didn't take too many of your illusions :-)
Regards