While waiting for some stuff to run, I came up with the following, Marine drop army (which would seem to be the same as E&Cs list) :-
200 Space Cruiser
350 Landing Craft #1
450 Tacticals with Rhinos + Razorback, Hunter and Captain
225 Assaults + Chaplain
350 Landing Craft #2
425 Tacticals with Rhinos + Razorback, Supreme Commander
300 Devastators with Rhinos + Librarian
200 THawk
200 Bikes
150 TBolts
150 TBolts
3000 points, 10 activations and completely "Fluffy" (well except for the extra bikes

). The Battle company and vehicles would planetfall, while the THawk flies in with the bikes as a mobile reserve, and the TBolts provide aircover and beats up broken formations.
Is it competitive - - - possibly not (lack of AT and any means to hurt titans), though it would certainly chew up a part of the opposing army, and there is enough mobility to get elsewhere (or bug out) fairly quickly.
Note, the Space Cruiser also applies the constraint on the number of units that can be fielded.
As an alternative, there is always the "Fluffy" 1st company drop army :-
200 Space Cruiser
350 Landing Craft
500 Terminators + 2x Dreadnoughts and Chaplain
350 Land Raiders
200 ThunderHawk
450 Terminators + Supreme Commander
200 ThunderHawk
400 Terminators + Librarian
350 Terminators (teleporting)
"Fluffy" and very tough, this also planetfalls to avoid enemy AA with the teleporting terminators as a reserve, but is not really competitive as it lacks sufficient mobility (apart from the transports - which are vulnerable to AA)