MLD Contact this place-

http://buyaero.com/

They might still have a Marutaka P38 in stock.

Or if you don't mind scratch building your own, I just got a set of plans Col. Art Johnson made for a P-38, 94 inch wingspan, .60 engine range I believe, from Ebay. There was just a set of Royal(Marutaka) P-38 plans for sale that ended yesterday or today. Search Ebay every few days for P-38 and P38, occasionally the Royal and Marutaka kits show up, that is where I got my very old Royal P-38 from 3 years ago. One of these days I'll get to finish it

There are quite a few places that will Laser cut a kit from plans. Just use a search engine and search for "Kit cutters".

If you wish, I have an original extra set of Royal(Marutaka) P-38 plans I can sell and send to you, however I am away on business right now and it will be another month at least until I can get them out of storage.

Good luck and don't give up hope!