I think Your talking about a Muggi, they were originally designed as slope fliers with out engines & I've seen full contact combat videos of them.
http://www.youtube.com/watch?v=GW7LMWha3jU
Then there is the EVO with a rear mounted elect pusher setup, this is the link
http://www.mugi.co.uk/evo_plans.php
As far as RC combat planes, they are not Deltas, #1 it's too hard to get a streamer and the deltas bleed off too much speed in tight turns and maneuvers + .30 are the largest engines used dew to setback rules for safety.
A 40 delta with the engine on the front is more like an Outlaw or Diamond Dust that are speed planes, You fly in long sweeping turns so they don't bleed off to much speed and fall out of the sky........
Then there is MrCleans Top Dawg which is a flat plate coro delta which are also a lot of fast fun.
Hope this helps
Jeff [8D]