Its a little labor intensive but I'm really ripping thru lvl 4 missions with these chars:

1x raven navy issue (faction fit DPS machine)
1x regular raven (mostly t2 fit for tank and some dps)
1x hurricane (salvager and extra scout drones)
1x myrmidon (has perfect siege warfare/leadership and medium drones)

Any suggestions for improvement?

upgrade the regular raven to a Golem
other than that pretty perfect, i run the same and have been for a while, not possible to do missions any faster

IMO drop the hurricane, you should have something like the regular raven or the myrm train for salvaging and drop one account. I only sudgest this because paying for 4 accounts is not very fun, and you wont have enough isk to buy plexes on l4 mission money. The only time I could see 4 accounts for missioning would be for a l5 mission, but 2 accounts are fine enough to run l4s like cake, 3 is a bit pushing the isk limit, and 4 is just losing isk unless you're paying out of pocket for all 4. (remember, if you were to pay for that 4th account, you better make it worth more then 350 mill isk, as thats how much the plex would be worth instead of it.)

The only time I'd see this working is if you replaced the myrm with an extra salvager and ran 2 groups of 2, so you'd be doing 2 missions at the same time. Doable, with really good income.

p-p-p-p-p-pattycake pattycake....

sorry I was distracted... oh, I don't need to say anything else..

I make most of my isk trading and manufacturing. I got the 4 accts to mine with initially and for production slots, etc. I only really started running missions for standings and the isk made is just a bonus. So while I see your point and think you're prolly right, im going to keep all 4 for the time being. Eventually i want all 4 to be somewhat pvp-capable..been testing 2x drake, 1xhurricane, 1x myrm