Here are a few dinghies (more or less within the LOA range you specified) which have a traveller/cart system :
-Byte (cat boat, main only; very similar to laser radial as per SA)
-CL 16 (sloop with spin option, not great to capsize/right tho)
-Hobie 16 (catamaran)
-Nacra 5.2 (catamaran)
-most albacores have a traveller system as well (be careful tho, I have seen some which had a bridle setup);
-Some older Int 420s might be found with an adjustable traveller or Club 420s have adjustable bridle systems.