nitro, here is pretty much the only place to get depron on the net http://www.depronusa.com/
you can also use blue core that can be picked up at lowes or home depot, that runs about 35.00 per pack of 23 sheets
also you can get resourcfull and find depron by picking up platters used for packing meat for the smaller parts, grocery stores, wal-mart, and party stores have them, I have had grocery stores just give me a few for the asking. Now I'm just guessing but using your deminsions I'm thinking your going to be around 19 to 23 oz AUW using full 3-D build depending on foam used, keeping that in mind I still feel your wing is going to be a weak point in relation to stable flight, deminsion wise it sounds good if wing TE and elev LE meet you will have 4.66" from wing LE to canard TE, if you stay with your current wing config I would suggest extra CF to prevent flexing or curling under hard manuvers, they are going to want to twist or tuck under at the tips at high speeds or hard turns, this can cause uncontrolable spiral dives as well as make it bad to tip stall. One last note with the exception of swept back full wings like on the F-18 as a rule of thumb you want the wing span to be greater than the fuse length, I think it can work and would like to see it when your done,,, so I am going to follow your post here I might get some ideas for mine as well, Good luck with it, I hope it works
That was a hint to turn this into a build thread or you could join us at fun with flat foam thread in the foamy section, we are trying to start a thread that covers all kinds of foam built planes, scratch ideas or tiled plans alike, most of us are begginners at building but I'm hoping to get some seasoned builders interested in sharing their ideas and builds there