I've also been playing since '04. I use roughly 9 accounts and some depending on what im doing. Also i do not use any multiboxing software for Eve as of yet. I really should try to incorporate it sometime though.

My solo/farm setup for haven/sanctums is usually: 5 Carriers 3 Tengus and 1 Scout alt. The setup i use is very much overkill, but it allows me to farm a whole system full of sanctums and havens. I can usually monopolize the whole circuit of those within a system. The money it yields on a daily basis is enough to pay for the accounts.

For my small gang fighting i use 5 Domis and 2 Scouts. This is my primary bait setup when im flying with friends or camping.

For fleets if im not flying a Logi or Triage Carrier, im usually flying in a fleet boosting Absolution.

I primarily do not use my carriers for anything but PvE and personal logics. When i fly mini-fleet around i usually have a rorqual and jump freighter in tow carrying most if not all my belongings. I do more often leave my rorqual collecting dust as i do not mine as much as i used to, and the JF with Cal V can go much further.

If i has to do this all over again, i would definitely go at least 3 toons maybe 4.

1 Carrier, 1 Tengu, 1 Scout, and 1 Salvager. That would be bare minimum for me to start all over with. That will be small enough to farm in 0.0 effectively and pay for the accounts themselves.