You have options avialable for a scratch built canard project. While Rutan stopped selling plans to the vari eze / long ez / defiant back in 1985, plans still turn up for premium prices.
If you just can't find the plans, you might try to purchase a copy of the plans from one of the thousands of builders out there. Most builders will not let there plans go, but might allow you to make a copy of their plans for a fee. Templets for the wings and Ronz canard should be easy to obtain from one of the past canard builders.
The e-racer might be another option for you. The e-racer mark ll is a side by side full retract version of the long eze with a lycoming located at the aft end. Many e-racer plan sets were sold with fewer built. The designer may not support the E-racer at this time, but plans are out there and turn up for sale now and then.
Also, Aircraft Spruce still sells cozy mark 4 plans, but does not support this aircraft.
With so many canard builders out there, you should be able to get all the support you need to build correctly and fly safely. Perhaps the support you need will be found in one of your local EAA chapters.