If you dont mind me asking,..why DD?
i know its the first manufacturer everyone thinks of when they go to buy a tarp,..(i have a 3x3 myself)
i also have a cheapo Quechua jobby, 3 x 3
and an issue basha at 2.5 x 2.75 ??
and i,ve just ordered a Tatonka 445 x 425 ,...
i just wondered why DD seems to be the first thing considered in most tarp conversations...
if its a bespoke item your planning then really ,..you could ask anyone to put something together for you,...with all the extra anchor points / tabs / etc etc you could possible need,.....
thats if a decent search about didnt uncover another manufacturer that may already even make a 4.5 x 4.5