Drinking again have we Gorthod?
In all seriousness, here's what I've got for the remaining levels:
20: Rogue (IMPR Evasion)
21: Blackguard (Armor Skin)
22: Blackguard
23: Blackguard (Epic Weapon Focus)
24: Blackguard (Epic Prowess)
25: Rogue
26: Rogue
27: Rogue (Defensive Roll, Epic Dodge)
28: Blackguard
29: Blackguard (Epic Blackguard Fiend)
Only variation I might make is taking epic skill focus in hide or spot instead of epic prowess. Note that you must take your 13th rogue level at level 27 to get epic dodge.