Well if you want to give it a shot I started doing the UNSC cruiser (using a perspective view, I can make a parallel sprite but it may look too flat) above and here is what I got if you are willing to do some bounding and such I can try to make more sprites
its at about 1:2.3 pixel/meter scale (by comparison your cov carrier is at at 1:5.2 pix/meter scale)
{"bounds":[625,-3,615,-15,625,-15,617,-25,607,-27,564,-61,468,-61,457,-69,313,-71,307,-71,299,-77,281,-75,272,-70,210,-71,198,-89,140,-87,131,-108,-97,-110,-103,-120,-253,-159,-276,-172,-446,-168,-464,-162,-509,-161,-488,-149,-495,-145,-509,-147,-529,-138,-530,-133,-558,-123,-572,-104,-602,-100,-620,-76,-622,75,-601,100,-576,101,-555,124,-532,133,-527,140,-510,146,-491,149,-487,154,-507,160,-509,165,-457,165,-447,168,-401,168,-397,173,-292,174,-287,179,-276,178,-263,168,-249,162,-105,123,-93,112,132,111,137,92,199,92,207,72,267,73,279,67,281,74,304,76,308,70,316,73,459,70,470,62,569,62,605,27,617,26,624,17,614,16,624,5],
"center":[-107,-229],"collisionRadius":"630","engineSlots":[{"angle":"180","contrailSize":"0","location":[-530,130],"length":"40","width":"50","style":"MIDLINE"},{"angle":"180","contrailSize":"0","location":[-624,2],"length":"100","width":"120","style":"MIDLINE"},{"angle":"180","contrailSize":"0","location":[-530,-130],"length":"40","width":"50","style":"MIDLINE"}],"height":509,"width":200,"hullId":"null","hullName":"Null","hullSize":"CAPITAL_SHIP","shieldCenter":[0,0],"shieldRadius":"0","spriteName":"path/to/sprite","style":"MIDLINE","viewOffset":0,"weaponSlots":[{"angle":"0","arc":"100","id":"Large 1","locations":[145,2],"mount":"TURRET","size":"LARGE","type":"BALLISTIC"},{"angle":"40","arc":"160","id":"LARGE 2","locations":[122,117],"mount":"TURRET","size":"LARGE","type":"BALLISTIC"},{"angle":"40","arc":"160","id":"LARGE 3","locations":[-122,117],"mount":"TURRET","size":"LARGE","type":"BALLISTIC"},{"angle":"0","arc":"5","id":"NEW","locations":[0,0],"mount":"TURRET","size":"SMALL","type":"ENERGY"}]}