with the DA50 -you are simply not talking to the right choir--
can an excellent pattern plane be done with the DA50 ?
absolutely-
but not at 11 lb -
that is a tough number to hit -even for guys with a lot of design background -but make no mistake - it can be done - just a little larger than the stuff you see as "2mm planes".
get some wood n slightly scale up something you see which appeals to you
there are no magic designs -just pick one easy to do .
as for the 3000 buck stuff -
PT Barnum had a phrase for it ---