There's a template from ELH for demiliches. The example monster (a 21st-level wizard) does have an official ECL of 33, implying an LA of +8 over and above lich's +4, but it's never given an LA as such.
Salient features of the template, as applied to a lich:
- +10 to all mental stats
- Size change to Diminutive for Medium-size races (doesn't actually state what happens to Smalls)
- Fly speed 180ft (perfect)
- Insight bonus equal to level on AC and attacks
- A bucket of SLAs, the highlights being Astral Projection, Create Undead/Greater Undead, Harm, SM 9 and Weird (all at will)
- Trap the Soul as (Su) targetting Fort
- Save DCs for the SLAs, paralysing touch and Trap the Soul are 10 + full HD + Cha
- Phylactery can "wear" a full set of magic items; demilich gets the bonuses
- The lich's +8 racial bonuses on detection/antidetection skills + Sense Motive all increase to +20
- Blinding Speed, Tenacious Magic and Auto-Quicken as bonus feats (only one of each), also Auto-Still on all spells (apparently including epic)
- A bucket of resistances: fire/acid/sonic resistance 20, turn resistance +20 (seemingly not intended to stack with Lich) and DR 15/epic and bludgeoning
- 3.0 Magic Immunity (still has the 3.0 text in the 3.5 SRD)
- Must pay 960,000 gp and 38,400 XP
Assuming for the sake of argument that the 3.0 Magic Immunity doesn't make the demilich immune to its own flight speed, phylactery transference, or Astral Projection/Harm SLAs, but does prevent any other spell/SLA/(Su) including its own, what LA would be balanced for this? (Discussion of stock Lich's probably-too-high LA is okay.)
My own thoughts: Since this is Epic territory, Thou Shalt Not Give Up Caster Levels is relaxed slightly; while you probably do want to grab a second set of 9ths (in order to get all three sets of epic spells per day from Epic Spellcasting), you're mostly only getting a bonus to caster level/skills/feats out of levels. The fact that you get a couple of actually-decent bonus feats from the template and +10 to mental stats almost requires an LA of +5 or more IMO. +25 to touch AC and +1 per level after that is possibly enough to actually matter. Phylactery Transference is good for avoiding Disjunctions. The save DCs on abilities scale well, although epic monsters can keep pace due to HD inflation. Perfect Automatic Still Spell negates ASF entirely (though there are other ways around it). And then there's Magic Immunity, which is a mess of an ability (whether the abilities I noted above trump it by RAW is unclear, since it's stated to be able to use them in the same thing giving it Magic Immunity; certainly they appear to do so in the example statblock). Does make it really hard to get around, because you're immune to teleportation and planeshift effects (possibly even Gate and Wish), which Astral Projection only somewhat mitigates (wearable items might be able to bypass this via Phylactery Transference, though). This also makes the +20 turn resistance kinda redundant, since Turn Undead is (Su). There's also the cost - this is basically all your WBL and well over a level's worth of XP at level 22, although by the 30s the GP cost's relatively minor.
