Homunculus really is the best you can do. A more acsessable solution would be a nice magic or rare. My favourite is the before mentioned Rhyme in a head with some nice +skills.
Also I would suggest taking a look at this runeword:
Very cheap and made in a nice wand (ex: +decrep, +RS, SM or whatever you find useful) it can be very powerful.
Hit Causes Monster To Flee 25%
+10 To Vitality
+3 To Poison and Bone Spells (Necromancer Only)
+3 To Bone Armor (Necromancer Only)
+2 To Bone Spear (Necromancer Only)
+4 To Skeleton Mastery (Necromancer Only)
Magic Damage Reduced By 4
20% Faster Cast Rate
+13 To Mana
If you get bored with the fishymancer I will (as I always do) suggest respeccing to mouseman's explosionmancer.
As the fishymancer it also relies heavily on corpse explosion - However, it doesn't use summons but kills with the bone spells instead. It is a very safe build as you can also make very good use of bone wall, bone armor and bone prison. The bone spells deals magic damage which means you won't encounter a lot of immune monsters - the ones you do meet can easily be killed by merc and CE.
I did one in HC myself and it can be completed with very cheap gear. Here's the stuff I used.