I can get the Cadac pretty hot with the griddle in place but not generally with the 1LB propane canisters - I need to use a bulk propane tank which seems to force out more propane. Same question you have - in pursuit of an ideal LP grill that's compact and will "really" sear a steak. In the field I use a Lodge griddle right on my LP stove and get it super hot then cook away - still not what we seem to be looking for but works pretty well. Won't char the meat as there is no flame touching the meat but not a bad option. Probably something you've already tried.
'07 Red Rock Jeep Sahara JKU
AT Habitat #12