Not many options as all the 'new' kits of classic pattern stuff is 60 sized. Kits occasionally appear on eBay. I don't fly electrics, but Eureka Aircraft Co. (Vintage Pattern Planes) sells some pattern kits that were designed in the late '60s to early '70s which were powered by fairly weak 60 sized engines of that time period. Most (like the Cutlass) fly very well on an OS 55AX, if that fits your available power source. I have a couple of 40-45 sized pattern kits which I probably won't build in this lifetime.. if you are interested: Yoshioka Citation 45, MK Atlas 40, MK Curare 40
Regards,
Will B.