1. Shriver is a Magical Location that bestows Regeneration 5/Good & Chaotic so Demons/Devils and most monsters won't be bypassing it.
2. Find a way to cast Favor of The Martyr (SpC), it's a 4th level spell that grants immunity to nonlethal damage.
= Immunity to all HP damage, no matter the type.
3. Add Soulfire (BoED) to your armor or bracers or robe.
= You're immune to all death effects, energy drain, and negative energy.
4. Play as an Azurin, it's like a Human but the extra skill points is replaced by +1 Essentia.
5. Take Shape Soulmeld(strongheart vest) as a feat.
6. Consider Extra Essentia as a 6th level feat.
= Reduce ability damage by 2 at level 1, if you take the second feat this improved to 3 at level 6 and 4 at level 12.
7. Get FoM.
= Immune to Grapples.
8. Buy Steadfast Boots.
= Extra +4 to opposed checks to resist Bullrush, Overrun, and Trip, also you get to attack anyone that charges you and deal double damage.
By no means perfect, but against Mundanes it can pretty much just stand there and laugh.
P.S.
Need higher Saves?
+5 Robe of the Vagabond of Resistance (CC/MiC, 26k): +5 resistance and +1 luck to saves.
+6 Empyreal Bracers of Armor (BoED, 64k): +6 sacred to saves, see A&E page 130 for rules on exchanging bonus types.
+5 Parry Spellstrike Gauntlet (SRD/MiC, 72k): +5 to saves vs spells and su/sp abilities & +1 insight to all saves.
Ioun Stone[Pale Green Prism](Core, 30k): +1 competence to saves.
Admiral's Bicorne (SW): +2 moral to saves, all nearby allies gain this benefit as well.
=14 to saves or +19 to saves vs magical stuff.