I'm personally making a summoning tank, end stats should be 80 defence/70 hitpoints/86 summoning at 48 combat. Rune minotaur's scroll is mage based and stuns the opponent. With the 80 defence/70 hitpoints I can easily tank mains and in the meantime I'll use the rune mino scroll to kill them and stun them. I might even get 95 summoning but a rune mino seems to be better in armour-on fights.
I think your best bet is actually a summoning tank but it takes a lot of time to get a high enough summoning level to win from mains. I've personally got around the time problem though by learning to script. My personal summoning tank script is around 95% done now and capable of getting 50-100 gold charms per hour depending on your summoning level. That's not bad at all considering it takes 35.000 gold charms from 52-86 summoning. Won't take much longer than 2 months to collect the charms for 86 summoning. I will probably be selling this script within 1-2 months after I'm done myself, so if you haven't decided by then check out the software sales forum